JP2010051040A - Motor controller for driving vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor controller for a vehicle having a cooling function, capable of avoiding a rise in temperature of the motor controller when circulation of a cooling medium in a cooling medium pipe is clogged. <P>SOLUTION: A control unit 26 obtains an estimated temperature of a cooling water based on a measured temperature of an IGBT equipped in each of a voltage step-up converter 12, a first inverter 14 and a second inverter 18. Also, the control unit 26 detects an abnormality of a cooling system based on the measured temperature of the IGBT equipped in each of the voltage step-up converter 12, the first inverter 14 and the second inverter 18 or the operation state of a pump 40. If the abnormality is detected, the control unit 26 controls a second motor generator 20 based on a torque limit value indicated by a torque limit map for a value obtained by adding an offset value to the estimated temperature. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle drive motor control device having a cooling function.

  Motor-driven vehicles such as hybrid vehicles and electric vehicles are widely used. A motor-driven vehicle is provided with a motor control device that performs drive control of the motor. The motor control device is provided with a refrigerant pipe for circulating cooling water. The cooling water flows through the refrigerant pipe by the driving force of the pump and cools the motor control device.

  When the refrigerant pipe is used for a long period of time, foreign matter accumulates inside, and the deposit may hinder the flow of cooling water. Further, when the pump reaches the end of its life, it becomes difficult to circulate the cooling water through the refrigerant pipe. In such a case, the temperature of the electrical components used in the motor control device may increase, and the life of the motor control device may be shortened.

  The present invention has been made for such a problem. That is, in the vehicle drive motor control device having a cooling function, an object is to avoid an increase in the temperature of the motor control device when an abnormality such as a stagnation of the refrigerant flow in the refrigerant pipe occurs.

JP 2007-195343 A JP 2002-191190 A JP 2001-45601 A JP 2005-176446 A

  The present invention includes a plurality of switching elements, an inverter that mutually converts DC power and AC power, cooling means that cools the switching elements with a refrigerant, and a torque command from a vehicle driving motor connected to the inverter. Control means for controlling the inverter so that an output torque corresponding to the value is output. In the vehicle drive motor control device, the control means includes an abnormality determination unit that determines abnormality of the cooling means, A temperature estimating unit for obtaining an estimated temperature of the refrigerant based on a temperature of the switching element; and the torque according to a corrected estimated value obtained by adding a positive offset value to the estimated temperature when the abnormality determining unit makes an abnormality determination. A torque command value determining unit for determining a command value.

  In the vehicle drive motor control device according to the present invention, the cooling means includes a pump for circulating the refrigerant, and the abnormality determination unit determines abnormality of the cooling means based on the temperature of the refrigerant. A first abnormality determining unit; and a second abnormality determining unit that determines an abnormality of the cooling unit based on an abnormality of the pump. The torque command value determining unit is configured to determine whether the first abnormality determining unit is abnormal. It is preferable that the offset value is set to a different value depending on whether the second abnormality determination means makes an abnormality determination.

  In the vehicle drive motor control device according to the present invention, the boost converter that adjusts a DC voltage and outputs the adjusted voltage to the inverter, and the temperature of the converter / switching element that is provided in the boost converter and is cooled by the cooling means are provided. Boosting converter element temperature detecting means for detecting, and inverter element temperature detecting means for detecting the temperature of the switching element provided in the inverter, wherein the temperature estimation unit is based on the detection result of the boosting converter element temperature detecting means. Refrigerant temperature estimating means for locally obtaining the estimated refrigerant temperature, refrigerant temperature estimating means for locally obtaining the estimated refrigerant temperature based on the detection result of the inverter element temperature detecting means, and the refrigerant obtained by each refrigerant temperature estimating means A variation value indicating a variation degree of the estimated temperature, and the temperature When the first abnormality determination unit makes an abnormality determination, the degree estimation unit obtains an estimated temperature of the refrigerant based on a maximum value among the refrigerant estimated temperatures obtained by each refrigerant temperature estimation unit, and the second When the abnormality determining means makes an abnormality determination, it is preferable to obtain the estimated temperature of the refrigerant based on the average value of the estimated refrigerant temperatures obtained by each refrigerant temperature estimating means.

  In the vehicle drive motor control device according to the present invention, the boost converter that adjusts a DC voltage and outputs the adjusted voltage to the inverter, and the temperature of the converter / switching element that is provided in the boost converter and is cooled by the cooling means are provided. Boosting converter element temperature detecting means for detecting, and inverter element temperature detecting means for detecting the temperature of the switching element included in the inverter, wherein the temperature estimation unit is based on the detection result of the boosting converter element temperature detecting means. Refrigerant temperature estimating means for locally obtaining the estimated refrigerant temperature; and refrigerant temperature estimating means for locally obtaining the estimated refrigerant temperature based on the detection result of the inverter element temperature detecting means, and obtained by each refrigerant temperature estimating means. The estimated temperature of the refrigerant is obtained based on the statistical value for the estimated refrigerant temperature. It is preferable.

  In the vehicle drive motor control device according to the present invention, the boost converter that adjusts a DC voltage and outputs the adjusted voltage to the inverter, and the temperature of the converter / switching element that is provided in the boost converter and is cooled by the cooling means are provided. Boosting converter element temperature detecting means for detecting, and inverter element temperature detecting means for detecting the temperature of the switching element provided in the inverter, wherein the temperature estimation unit is based on the detection result of the boosting converter element temperature detecting means. Refrigerant temperature estimating means for locally obtaining the estimated refrigerant temperature, refrigerant temperature estimating means for locally obtaining the estimated refrigerant temperature based on the detection result of the inverter element temperature detecting means, and the refrigerant obtained by each refrigerant temperature estimating means Means for obtaining a variation value indicating a variation degree of the estimated temperature, The estimated temperature of the refrigerant is obtained based on the estimated refrigerant temperature obtained from the detection result of the pressure converter element temperature detecting means, or the refrigerant is estimated based on a statistical value for the estimated refrigerant temperature obtained by each refrigerant temperature estimating means. It is preferable to determine whether to obtain the temperature based on the variation value, and to obtain the estimated temperature of the refrigerant according to the determination result.

  In the vehicle drive motor control device according to the present invention, it is preferable that the torque command value determining unit sets the offset value to a different value according to the variation value.

  In the vehicle drive motor control device according to the present invention, the torque command value determining unit has a torque defining relationship defined between the median value for determining the torque command value and the torque command value. Torque determining means for determining the torque command value based on the torque determining means, and when the abnormality determining section determines normality, the torque determining means determines the torque command value using the temperature of the refrigerant as the median value, and When the determination unit makes an abnormality determination, it is preferable to determine the torque command value using the corrected estimated value as the median value.

  Further, in the vehicle drive motor control device according to the present invention, the control means includes an initial torque command value determining unit that obtains an initial value of a torque command value based on a driving operation of the vehicle, and the torque regulation relationship is: It is preferable that the ratio of the torque command value to the initial value becomes smaller as the median value becomes larger.

  ADVANTAGE OF THE INVENTION According to this invention, in the vehicle drive motor control apparatus which has a cooling function, the temperature rise of the vehicle drive motor control apparatus by abnormality of a cooling function can be avoided.

  FIG. 1 shows a configuration of a hybrid vehicle drive system according to an embodiment of the present invention. Boost converter 12 boosts the voltage of battery 10 under the control of control unit 26 and outputs the boosted voltage to first inverter 14 and second inverter 18. The first inverter 14 and the second inverter 18 convert a DC voltage into a three-phase AC voltage according to the control of the control unit 26, and output the three-phase AC voltage to the first motor generator 16 and the second motor generator 20, respectively. To do. First inverter 14 and second inverter 18 convert the three-phase AC power generation voltages of first motor generator 16 and second motor generator 20 into DC voltages, respectively, and output the DC voltages to boost converter 12.

  The first motor generator 16 receives power from the battery 10 via the boost converter 12 and the first inverter 14 according to the magnitude relationship between the induced electromotive force of the first motor generator 16 and the output voltage of the first inverter 14. Give and receive. The first motor generator 16 is accelerated by supplying electric power from the battery 10 to the first motor generator 16, and the first motor generator 16 is decelerated by supplying electric power from the first motor generator 16 to the battery 10. . The electric power exchanged between the first motor generator 16 and the battery 10 can be adjusted by the control unit 26 controlling the first inverter 14.

  Similarly, the second motor generator 20 is connected to the battery 10 via the boost converter 12 and the second inverter 18 in accordance with the magnitude relationship between the induced electromotive force of the second motor generator 20 and the output voltage of the second inverter 18. Send and receive power between them. The second motor generator 20 is accelerated by supplying electric power from the battery 10 to the second motor generator 20, and the second motor generator 20 is decelerated by supplying electric power from the second motor generator 20 to the battery 10. . The electric power exchanged between the second motor generator 20 and the battery 10 can be adjusted by the control unit 26 controlling the second inverter 18. Each of the first motor generator 16 and the second motor generator 20 includes a resolver that detects the rotation speed, and outputs the detection result to the control unit 26.

  The engine 22 operates according to the control of the control unit 26. The power transmission mechanism 24 transmits torque between the first motor generator 16, the second motor generator 20, and the engine 22. The combined torque appearing on the shaft of second motor generator 20 is transmitted to the wheels. The first motor generator 16 is used for starting the engine 22, charging the battery 10, and the like.

  The operation unit 28 includes an accelerator pedal, a brake pedal, a gear change lever, a steering, and the like, and outputs a driving operation command to the control unit 26. The control unit 26 obtains torque command values for the first motor generator 16, the second motor generator 20, and the engine 22 based on the driving operation command, and based on the obtained torque command values, the boost converter 12, The first inverter 14, the second inverter 18, and the engine 22 are controlled.

  The refrigerant pipe 38 is piped in contact with the boost converter 12, the first inverter 14 and the second inverter 18. A pump 40 is attached to the start point and the end point of the refrigerant pipe 38. The pump 40 operates according to the control of the control unit 26 and circulates cooling water through the refrigerant pipe 38. The control unit 26 can detect whether or not the pump 40 is operating normally. A water temperature sensor 42 provided in the refrigerant pipe 38 measures the temperature of the cooling water and outputs the measurement result to the control unit 26.

  Boost converter 12 includes a switching element and an inductor. Boost converter 12 generates an induced electromotive force in the inductor by on / off control of the switching element, and outputs a voltage obtained by adding the induced electromotive force to the output voltage of battery 10. As the switching element, a transistor, a thyristor, a triac, or the like can be used. In the case of using a transistor, it is preferable to employ an IGBT (Insulated Gate Bipolar Transistor) in order to ensure insulation from the outside of the boost converter 12. In the present embodiment, it is assumed that the boost converter 12 includes two IGBTs.

  FIG. 2A shows a configuration example of the boost converter 12. The control unit 26 performs on / off control between the collector terminal C and the emitter terminal E of each IGBT by controlling the voltage between the gate terminal G and the emitter terminal E of each IGBT.

  The emitter terminal E of the IGBT 54 is connected to the collector terminal C of the IGBT 52. An inductor 50 is connected between the low voltage side terminal 46 and the connection point between the IGBTs 52 and 54. The emitter terminal E of the IGBT 52 is connected to the low voltage side terminal 48 and the high voltage side terminal 60. The collector terminal C of the IGBT 54 is connected to the high voltage side terminal 58. A capacitor 56 is connected between the high voltage side terminal 58 and the high voltage side terminal 60.

  A DC voltage is applied between the low voltage side terminal 46 and the low voltage side terminal 48. An induced electromotive force is generated in the inductor 50 by turning on and off the IGBT 54. By turning on the IGBT 52, a voltage obtained by adding the inductor induced electromotive force to the voltage applied between the low voltage side terminal 46 and the low voltage side terminal 48 is applied between the terminals of the capacitor 56. The terminal voltage of the capacitor 56 is output from the high voltage side terminals 58 and 60. The control unit 26 controls the IGBTs 52 and 54 alternately to turn on and off, so that a voltage obtained by adding the inductor induced electromotive force to the voltage applied to the low voltage side terminals 46 and 48 becomes the high voltage side terminal 58 and the boosted voltage. 60.

  The first IGBT temperature sensor 30 measures the temperature of one of the two IGBTs included in the boost converter 12 and outputs the measurement result to the control unit 26. The second IGBT temperature sensor 32 measures the temperature of the other IGBT and outputs the measurement result to the control unit 26.

  Each of the first inverter 14 and the second inverter 18 includes six switching elements. Each phase current of the input / output three-phase alternating current of the first inverter 14 and the second inverter 18 flows when two of the six switching elements corresponding to each phase current are turned on. Each inverter converts a DC voltage into a three-phase AC voltage or converts a three-phase AC voltage into a DC voltage by on / off control of the switching element. As the switching element, a transistor, a thyristor, a triac, or the like can be used as in the boost converter 12, and when a transistor is used, it is preferable to employ an IGBT. In the present embodiment, IGBTs are used for the first inverter 14 and the second inverter 18.

  FIG. 2B shows a configuration example of the first inverter 14 and the second inverter 18. The control unit 26 performs on / off control between the collector terminal C and the emitter terminal E of each IGBT by controlling the voltage between the gate terminal G and the emitter terminal E of each IGBT.

  Each collector terminal C of IGBTs 66, 68, and 70 is connected to DC positive terminal 62. The emitter terminals E of the IGBTs 72, 74, and 76 are connected to the DC negative terminal 64. Emitter terminals E of IGBTs 66, 68, and 70 are connected to collector terminals C of IGBTs 72, 74, and 76, respectively. The connection points of IGBTs 66 and 72, the connection points of IGBTs 68 and 74, and the connection points of IGBTs 70 and 76 are connected to the u-phase terminal, the v-phase terminal, and the w-phase terminal, respectively.

  As the switching state of the inverter shown in FIG. 2B, the following six states can be taken. (1) By turning on the IGBTs 66 and 74, a voltage is applied between the u-phase terminal and the v-phase terminal with the u-phase terminal side being positive. (2) By turning on the IGBTs 68 and 72, A state in which a voltage is applied with the v-phase terminal side being positive between the u-phase terminal and the v-phase terminal. (3) By turning on the IGBTs 68 and 76, the v-phase terminal is connected between the v-phase terminal and the w-phase terminal. A state in which a voltage is applied with the terminal side being positive, and (4) a state in which the voltage is applied with the w-phase terminal side being positive between the v-phase terminal and the w-phase terminal by turning on the IGBTs 70 and 74. ) By turning on IGBTs 70 and 72, a voltage is applied between the w-phase terminal and the u-phase terminal with the w-phase terminal side being positive. (6) By turning on IGBTs 66 and 76, the w-phase terminal is turned on. Between terminal and u terminal When a voltage is applied to the phase terminal side as a positive.

  The control unit 26 combines the switching states of any one of the above (1) to (6), and changes the combination of the switching states over time, so that the DC unit is connected between the DC positive terminal 62 and the DC negative terminal 64. The applied DC voltage is converted into a three-phase AC voltage and output to the u-phase terminal, the v-phase terminal, and the w-phase terminal, or the three-phase applied to the u-phase terminal, the v-phase terminal, and the w-phase terminal The AC voltage is converted into a DC voltage and output between the DC positive terminal 62 and the DC negative terminal 64. In the state (1) or (2), current flows in the uv phase, and in the state (3) or (4), current flows in the vw phase. In the state (5) or (6), a current flows in the wv phase.

  The first inverter temperature sensor 34 measures the temperature of one of the six IGBTs included in the first inverter 14 and outputs the measurement result to the control unit 26. The second inverter temperature sensor 36 measures the temperature of one of the six IGBTs included in the second inverter 18 and outputs the measurement result to the control unit 26.

  Next, control for avoiding a temperature rise of the second inverter 18 will be described. In the hybrid vehicle drive system, when the rotation of the second motor generator 20 is hindered due to the wheels locking or the like, and the three-phase AC current flowing through the second motor generator 20 increases, the following problem occurs. That is, the increase in the three-phase alternating current flowing through the second motor generator 20 increases the amount of heat generated by the IGBT of the second inverter 18, resulting in a problem that the life of the IGBT is shortened.

  Therefore, the control unit 26 refers to the torque limit map stored in the torque limit map storage unit 44 when the rotation speed detection value acquired from the second motor generator 20 becomes less than a predetermined value.

  Here, as shown in FIG. 3, the torque limit map is a map in which the limit value determining value and the torque limit value are associated with each other and the torque limit value is obtained by giving a certain limit value determining value. The torque limit value is a value that limits the torque command value finally obtained by multiplying the initial torque value obtained by the control unit 26 as the torque to be generated by the second motor generator 20. The torque limit value has a value of 0% to 100%, and is a ratio of the finally obtained torque command value to the initial torque value. A torque limit value of 100% means that no torque limit is applied, and a torque limit value of 0% means that torque generation is prohibited.

  In the torque limit map shown in FIG. 3, when the limit value determination value is less than T1, the torque limit value is a constant value of 100%. Then, when the limit value determination value is equal to or greater than T1, the limit value determination value and the torque limit value are associated with each other so that the torque limit value decreases as the limit value determination value increases. Further, in the torque limit map shown in FIG. 3, the slope when the limit value determination value is T2 or more is larger than the slope when the limit value determination value is T1 or more and less than T2, and the limit value determination value is T3. The limit value determination value and the torque limit value are associated with each other so that the torque limit value becomes 0%.

  Here, the limit value determination value is obtained by referring to the torque limit map stored in the torque limit map storage unit 44. In addition to such a configuration, a configuration may be used in which a function having a limit value determination value as an independent variable and a torque limit value as a dependent variable is used. In this case, a function generator is provided instead of the torque limit map storage unit 44. The function generator obtains a torque limit value for the limit value determination value output from the control unit 26 based on a function representing the characteristic shown in FIG.

  The control unit 26 refers to the torque limit map using the measured temperature of the water temperature sensor 42 as a limit value determination value, and acquires a torque limit value for the measured temperature of the water temperature sensor 42. Then, the torque command value is obtained by multiplying the initial torque value obtained as the torque to be generated by the second motor generator 20 by the torque limit value. Control unit 26 controls boost converter 12 and second inverter 18 based on the torque command value.

  According to such a control at the time of locking, when the rotation of the second motor generator 20 is hindered due to the wheel locking or the like, the second inverter 18 and the accompanying cooling water temperature rise together with the second temperature. The torque command value for motor generator 20 is limited. As a result, the current flowing through the IGBT of the second inverter 18 is also limited, and it is possible to avoid shortening the lifetime of the IGBT due to heat generation.

  As described above, the refrigerant pipe 38 may accumulate foreign matter inside the long-term use, and the deposit may hinder the flow of the cooling water. In addition, when the pump 40 reaches the end of its life, it becomes difficult to circulate cooling water through the refrigerant pipe 38. The hybrid vehicle drive system according to the present embodiment performs the control described below when an abnormality occurs in the cooling system, and avoids the temperature increase of the second inverter 18.

  In the above-described control at the time of locking, the second inverter 18 is controlled based on the measured temperature of the water temperature sensor 42 so that the torque limit value of the second motor generator 20 is limited, and the current flowing through the IGBT of the second inverter 18 is limited. To do. Accordingly, the temperature of the second inverter 18 rises when the temperature of the cooling water near the water temperature sensor 42 rises, and the temperature of the second inverter 18 also falls when the temperature of the cooling water near the water temperature sensor 42 falls. Appropriate control can be performed when there is a relationship.

  However, when the circulation of the cooling water is stagnant, such a relationship is not necessarily established between the temperature of the cooling water near the water temperature sensor 42 and the temperature of the second inverter 18. Therefore, there is a possibility that sufficient current limitation may not be performed even though the amount of heat generated by the IGBT of the second inverter 18 is excessive. Therefore, the control unit 26 performs cooling water temperature estimation control described below.

  The principle of the coolant temperature estimation control will be described. The measured temperatures output from the first IGBT temperature sensor 30, the second IGBT temperature sensor 32, the first inverter temperature sensor 34, and the second inverter temperature sensor 36 indicate the element temperature of the IGBT fixedly arranged in the hybrid vehicle drive system. Therefore, by obtaining in advance the correspondence relationship between the temperature of the cooling water flowing through the refrigerant pipe 38 and the temperature change (time change rate) of each IGBT within a predetermined time at the design stage, the time change of the measured temperature. The temperature of the cooling water can be estimated based on the rate. Thereby, the control unit 26 estimates the temperature of the cooling water based on the measured temperature of each sensor.

  The control unit 26 includes a boost converter first estimated temperature calculation unit C1, a boost converter second estimated temperature calculation unit C2, a first inverter estimated temperature calculation unit I1, and a second inverter estimated temperature calculation unit I2.

  Boost converter first estimated temperature calculation unit C1 obtains estimated temperature TC1 based on the temporal change rate of the measured temperature of first IGBT temperature sensor 30. Further, the boost converter second estimated temperature calculation unit C2 obtains the estimated temperature TC2 based on the time change rate of the measured temperature of the second IGBT temperature sensor 32.

  Similarly, the first inverter estimated temperature calculation unit I1 obtains the estimated temperature TI1 based on the time change rate of the measured temperature of the first inverter temperature sensor 34. Further, the second inverter estimated temperature calculation unit I2 obtains the estimated temperature TI2 based on the time change rate of the measured temperature of the second inverter temperature sensor 36.

  Next, processing executed by the control unit 26 using each estimated temperature will be described with reference to the flowchart of FIG. The control unit 26 obtains the maximum value Tx among the estimated temperatures TC1, TC2, TI1, and TI2 (S101). Then, it is determined whether or not the maximum value Tx is equal to or greater than a predetermined threshold value TH1 (S102). When the maximum value Tx is equal to or greater than the predetermined threshold value TH1, the control unit 26 sets the value as the final estimated temperature TE (S103).

  When the circulation of the cooling water is stagnant, at least one of the estimated temperatures TC1, TC2, TI1, and TI2 increases. Therefore, when the maximum value among these estimated temperatures is equal to or higher than the threshold value TH1, there is a high possibility that the circulation of the cooling water is stagnant. According to steps S101 to S103, the maximum temperature estimated when the circulation of the cooling water is stagnating can be obtained as the final estimated temperature TE.

  Next, the control unit 26 obtains a value obtained by adding the offset value Of1 to the final estimated temperature TE as the limit value determination value Td (S104). Then, a torque limit value corresponding to the limit value determination value Td is obtained with reference to the torque limit map (S105). The control unit 26 controls the boost converter 12 and the second inverter 18 based on the torque command value obtained using the torque limit value (S106).

  According to such a process, the value obtained by adding the offset value Of1 to the final estimated temperature TE is set as the limit value determination value Td, and the second motor generator 20 based on the torque limit value corresponding to the limit value determination value Td. Control is performed. That is, the control using the virtual map shown in FIG. 5 (a) in which the horizontal axis of the torque limit map of FIG. 3 is the final estimated temperature TE and the characteristic is moved by the offset value Of1 in the negative direction of the horizontal axis. The same control can be performed.

  Processing when the maximum value Tx is less than the predetermined threshold value TH1 will be described (S102). The control unit 26 determines whether or not the pump 40 is operating normally (S107). When the pump 40 does not operate normally and is stopped, the average value Ta of the estimated temperatures TC1, TC2, TI1, and TI2 is obtained (S108), and the average value Ta is set as the final estimated temperature TE (S109). .

  The control unit 26 obtains a value obtained by adding the offset value Of2 to the final estimated temperature TE as the limit value determination value Td (S110). Here, the offset value Of2 is set to a value smaller than the offset value Of1, for example. The control unit 26 refers to the torque limit map to obtain a torque limit value corresponding to the limit value determining value Td (S105), and based on the torque command value obtained using the torque limit value, the control unit 26 and the second The inverter 18 is controlled (S106).

  Here, it is determined in step S107 that the pump 40 is not operating normally because the pump 40 is stopped although the maximum value Tx has not risen to the threshold value TH1, and therefore, in the future, the boost converter 12. This is a case where the temperature of the IGBT of the first inverter 14 or the second inverter 18 may increase. According to steps S107 to S109, the temperature of the cooling water before the IGBT temperature of these power circuits rises is obtained as the final estimated temperature TE.

  Then, the value obtained by adding the offset value Of2 to the final estimated temperature TE is set as a limit value determination value Td, and the second motor generator 20 is controlled based on the torque limit value corresponding to the limit value determination value Td. That is, the control is the same as the control using the virtual map shown in FIG. 5B in which the horizontal axis of the torque limit map in FIG. 3 is the final estimated temperature and the characteristic is moved by the offset value Of2 in the negative direction of the horizontal axis. Is controlled.

  On the other hand, when the pump 40 is operating normally, the control unit 26 performs normal locking control based on S111, S105, and S106. That is, the control unit 26 sets the measured temperature of the water temperature sensor 42 as the limit value determining value Td (S111). Then, referring to the torque limit map, a torque limit value corresponding to limit value determining value Td is obtained (S105), and boost converter 12 and second inverter 18 are based on the torque command value obtained using the torque limit value. Is controlled (S106).

  According to the cooling water temperature estimation control, the following effects can be obtained. The estimated temperatures TI1 and TI2 are estimated temperatures based on the temperature of one of the six IGBTs included in the inverter. Each phase current of the input / output three-phase alternating current of the inverter flows when two of the six IGBTs corresponding to each phase current are turned on.

  Therefore, even when the magnitude of the current of one phase of the three-phase AC current flowing through the motor generator increases and the amount of heat generated by the IGBT that is not the temperature detection target increases, The calorific value is not reflected in the estimated temperature TI1 or TI2. As a result, an error occurs in the final estimated temperature TE with respect to the actual cooling water temperature. Therefore, when the torque limit value is obtained as it is using the final estimated temperature TE obtained based on the estimated temperatures TI1 and TI2, sufficient current limitation may not be applied to the IGBT that is not subject to temperature detection. is there.

  Therefore, in steps S104 and S110, a limit value determination value Td obtained by adding an offset value to the final estimated temperature TE is obtained. The offset values Of1 and Of2 are determined to be optimum values based on experiments or simulations so that the IGBT is protected. As a result, an error between the final estimated temperature TE and the actual cooling water temperature can be compensated, and an appropriate current limit can be applied.

  Further, by setting the offset value Of2 to a value smaller than the offset value Of1, it is possible to appropriately limit the current according to the calculation process of the final estimated temperature TE. That is, the final estimated temperature TE obtained in step S103 is the maximum cooling water temperature estimated when there is a high possibility that the temperature of the cooling water is actually rising, whereas the final estimated temperature TE obtained in step S109. The estimated temperature TE is a coolant temperature estimated when the pump 40 is not operating normally but it is unlikely that the coolant temperature is actually rising. Therefore, setting the offset value Of2 to the same value as the offset value Of1 and applying a current limit as when the temperature actually increases results in an excessive torque limit, which is not preferable from the viewpoint of running performance. Therefore, by setting the offset value Of2 to a value smaller than the offset value Of1, an appropriate current limit can be applied.

  Here, the process of obtaining the maximum value Tx of the estimated temperatures TC1, TC2, TI1, and TI2 (S101) and determining whether the maximum value Tx is equal to or greater than the threshold value TH1 has been described (S102). In addition to such processing, the average value Ta of the estimated temperatures TC1, TC2, TI1, and TI2 is obtained, it is determined whether the average value Ta is equal to or greater than a predetermined threshold value TH2, and processing based on the determination result is performed. You may go. In this case, when the average value Ta is equal to or greater than the predetermined threshold value TH2, the maximum value Tx of the estimated temperatures TC1, TC2, TI1, and TI2 is obtained, and the process proceeds to step S103. On the other hand, when the average value Ta is less than the predetermined threshold value, the process proceeds to step S107. Since the average value Ta is obtained in the previous step, it is not always necessary to execute the process of S108 from the process of S107 to the process of S109.

  Next, the cooling water temperature estimation control according to the application example will be described. FIG. 6 shows a flowchart of applied cooling water temperature estimation control. The same steps as those in the flowchart of FIG. 4 are denoted by the same reference numerals, and the description thereof is omitted. In the applied cooling water temperature estimation control, a process for determining whether or not the average value Ta is equal to or greater than a predetermined threshold TH2 is executed instead of the process of step S101 for determining whether or not the maximum value Tx is equal to or greater than the threshold TH1. To do. Further, the effectiveness of the final estimated temperature TE is determined between steps S104 and S105 of the cooling water temperature estimation control or between steps S110 and S105, and when it is determined that the final estimated temperature TE is not effective, the final estimated temperature TE is appropriately set. Change to a correct value.

  The control unit 26 obtains an average value Ta of the estimated temperatures TC1, TC2, TI1, and TI2 (S201). And it is determined whether average value Ta is more than predetermined threshold TH2 (S202). When the average value Ta is equal to or greater than the predetermined threshold value TH2, the control unit 26 obtains the maximum value Tx of the estimated temperatures TC1, TC2, TI1, and TI2 (S203), and uses that value as the final estimated temperature TE. (S103). On the other hand, when the average value Ta is less than the predetermined threshold value, the control unit 26 proceeds to the process of step S107. Since the average value Ta is obtained in step S201, here, the process for obtaining the average value Ta again is not executed during the period from the process of S107 to the process of S109.

  After executing the process of step S104 or step S110, the control unit 26 obtains the variation D of the estimated temperatures TC1, TC2, TI1, and TI2 (S204). The variation D is based on, for example, the variance of the estimated temperatures TC1, TC2, TI1, and TI2, the weighted average value of the difference between these estimated temperatures, the difference between the minimum and maximum values of these estimated temperatures, etc. Can be defined. If the cooling water flows through the refrigerant pipe 38 without any delay, the estimated cooling water temperature obtained based on the time change rate of the measured temperature is substantially the same for each temperature sensor. However, when the circulation of the cooling water is stagnant, the estimated cooling water temperature obtained by the measured temperature of each temperature sensor varies, and the final estimated temperature TE obtained based on each estimated cooling water temperature is changed. Reliability is reduced. In the applied coolant temperature estimation control, the effectiveness of the final estimated temperature TE is determined based on such a principle.

  The control unit 26 determines whether or not the variation D is greater than or equal to a predetermined threshold value TH3 (S205). When the variation D is equal to or greater than the predetermined threshold TH3, the larger one of the estimated temperatures TC1 and TC2 is updated as the final estimated temperature TE (S206). Then, a value obtained by adding the offset value Of3 to the final estimated temperature TE is obtained as the limit value determination value Td (S207), and the process proceeds to step 105. Here, the offset value Of3 is determined based on an experiment or simulation so that the IGBT is protected.

  When the variation is less than the predetermined threshold value TH3, the control unit 26 maintains the limit value determination value Td obtained before Step 202 is executed, and proceeds to Step 105. The control unit 26 refers to the torque limit map to determine a torque limit value corresponding to the limit value determination value Td (S105), and based on the torque command value calculated using the torque limit value, the boost converter 12 and the second inverter 18 is controlled (S106).

  According to such a process, even if the reliability as the value indicating the temperature of the final estimated temperature TE is low, the limit value determination value can be determined. At that time, a limit value determination value for sufficiently limiting current can be determined by obtaining the larger one of the estimated temperatures TC1 and TC2 as the final estimated temperature TE. The reason is as follows.

  The estimated temperatures TI1 and TI2 are estimated temperatures based on the temperature of one of a plurality of IGBTs included in the inverter. Therefore, when the magnitude of the current of one phase of the three-phase alternating current flowing through the motor generator increases and the heat generation amount of the IGBT that is not the temperature detection target increases, the heat generation amount of the IGBT that is not the temperature detection target. May not be reflected in the estimated temperature TI1 or TI2, and an appropriate current limit may not be applied.

  On the other hand, estimated temperatures TI1 and TI2 are estimated temperatures based on the IGBT temperature of boost converter 12 that inputs and outputs a single-phase DC voltage. Therefore, regardless of which phase of the three-phase alternating current flowing through the motor generator has increased, the increase in current flowing through boost converter 12 is reflected in estimated temperatures TC1 and TC. Therefore, the limit value determination value Td for sufficient current limitation can be determined by obtaining the larger one of the estimated temperatures TC1 and TC2 as the final estimated temperature TE as in the application example.

  Further, according to this application example, the value obtained by adding the offset value Of3 to the final estimated temperature TE is set as the limit value determining value Td, and the second motor generator 20 based on the torque limit value corresponding to the limit value determining value Td. Is controlled. That is, the control is the same as the control using the virtual map shown in FIG. 5C in which the horizontal axis of the torque limit map in FIG. 3 is the final estimated temperature and the characteristic is moved by the offset value Of3 in the negative direction of the horizontal axis. Can be controlled.

  Therefore, it is possible to limit the torque in the range of the final estimated temperature TE on the side where the value is smaller than the range of the limit value determination value to which the torque limit is applied. Thereby, even if the circulation of the cooling water is stagnant, sufficient current limitation can be performed on the IGBT of the second inverter 18.

  In the above description, the processing using the torque limit map shown in FIG. 3 has been described. In the torque limit map of FIG. 3, when the limit value determination value Td is equal to or greater than T3, the torque limit value becomes 0, and the vehicle is not started. However, it is preferable to control the second motor generator 20 so that the minimum necessary torque is generated even when the wheels are locked or the like. Therefore, when the torque limit value acquired based on the torque limit map becomes less than the minimum value TL, minimum limit control for forcibly setting the torque limit value to TL may be performed. However, the minimum limit control is performed when the difference between the final estimated temperature TE and the design allowable temperature of the IGBT of the second inverter 18 is larger than a predetermined margin. By performing the minimum limit control, the same control as the control using the virtual map shown in FIG. 7 in which the minimum value of the characteristic of the torque limit map is limited to TL can be performed.

  Next, a second application example will be described. In the conventional hybrid vehicle drive system, when the measured temperature of the water temperature sensor 42 is less than a predetermined threshold value, the control unit 26 controls the boost converter so that the inverter-side output voltage of the boost converter 12 does not exceed a predetermined upper limit value. 12 controls were performed. As a result, the insulation performance between the boost converter 12 and the inverter body and the like due to a decrease in the cooling water temperature is reduced, and a failure or the like is avoided.

  However, when the circulation of the cooling water is delayed, there is a high possibility that the measured temperature of the water temperature sensor 42 does not accurately indicate the cooling water temperature. If the measured temperature exceeds the threshold value even though the actual water temperature is less than the threshold value, the inverter-side output voltage of the boost converter 12 is controlled to be high, which may cause a failure or the like. Therefore, in the OVH restriction control described below, when there is a high possibility that the circulation of the cooling water is stagnant, control is performed to reduce the upper limit value OVH of the output voltage of the boost converter 12.

  FIG. 8 shows a flowchart of the OVH restriction control. The same steps as those in the flowcharts of FIGS. 4 and 6 are denoted by the same reference numerals, and description thereof is omitted.

  When executing step S111, the control unit 26 sets the boost converter output voltage upper limit value OVH according to the measured temperature of the water temperature sensor 42 (S302), and proceeds to the process of step S105. Boost converter output voltage upper limit value OVH is set to voltage value VH, for example, when measured temperature is equal to or higher than a predetermined threshold value, and is set to voltage value VL when measured temperature is lower than the predetermined threshold value. Here, the voltage value VL is smaller than the voltage value VH.

  In addition, when step S104 or step S110 is executed, the control unit 26 sets the upper limit value OVH of the boost converter output voltage to the voltage value VL (S301), and proceeds to the process of step S204.

  In step 106, control unit 26 controls boost converter 12 so that the inverter-side output voltage of boost converter 12 does not exceed boost converter output voltage upper limit value OVH set in step S301 or S302.

  According to such processing, when there is a high possibility that the circulation of the cooling water is stagnant, step S104 or step S110 is executed and the boost converter output voltage upper limit value OVH is set to the voltage value VL. . When the possibility that the circulation of the cooling water is stagnant is low, step S111 is executed and the boost converter output voltage upper limit value OVH corresponding to the measured temperature of the water temperature sensor 42 is set.

  Therefore, when there is a high possibility that the circulation of the cooling water is stagnant, upper limit value OVH of boost converter output voltage is forcibly set to voltage value VL. Therefore, even when the circulation of the cooling water is stagnant and the measured temperature of the water temperature sensor 42 does not accurately indicate the cooling water temperature, the output voltage of the boost converter 12 can be limited to a low value. As a result, the insulation performance between the boost converter 12 and the inverter body and the like can be prevented from being reduced, and a failure or the like can be avoided.

  Although the above embodiment and the application example thereof have been described when water is used as the refrigerant, a fluid such as chlorofluorocarbon or ammonia may be used as the refrigerant. Although the control of the second motor generator 20 has been described above, the present invention can also be used for the control of the first motor generator 16. Furthermore, the present invention can be used not only for hybrid vehicles but also for electric vehicles. In this case, the engine 22 may be removed from the above-described embodiment, and one of the first motor generator 16 and the second motor generator 20 may be used for driving, and the other may be used for regenerative power generation.

It is a figure which shows the structure of a hybrid vehicle drive system. It is a figure which shows each structural example of a boost converter and an inverter. It is a figure which shows a torque limitation map. It is a flowchart of cooling water temperature estimation control. It is a figure which shows the virtual torque limitation map which concerns on cooling water temperature estimation control. It is a flowchart of application cooling water temperature estimation control. It is a figure which shows the virtual torque limitation map which concerns on minimum limit control. It is a flowchart of OVH restriction | limiting control.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Battery, 12 Boost converters, 14 1st inverter, 16 1st motor generator, 18 2nd inverter, 20 2nd motor generator, 22 Engine, 24 Power transmission mechanism, 26 Control unit, 28 Operation part, 30 1st IGBT temperature sensor , 32 2nd IGBT temperature sensor, 34 1st inverter temperature sensor, 36 2nd inverter temperature sensor, 38 refrigerant pipe, 40 pump, 42 water temperature sensor, 44 torque limit map storage unit, 46, 48 low voltage side terminal, 50 inductor, 52, 54, 66 to 76 IGBT, 56 capacitor, 58, 60 high voltage side terminal, 62 DC positive terminal, 64 DC negative terminal, C1 boost converter first estimated temperature calculator, C2 boost converter second estimated temperature calculator, I1 Estimated temperature of the first inverter Calculation unit, I2 second inverter estimated temperature calculating unit.

Claims (8)

An inverter that includes a plurality of switching elements and that converts between DC power and AC power;
Cooling means for cooling the switching element with a refrigerant;
Control means for controlling the inverter so that an output torque corresponding to a torque command value is output from a vehicle driving motor connected to the inverter;
In a vehicle drive motor control device comprising:
The control means includes
An abnormality determination unit for determining abnormality of the cooling means;
A temperature estimation unit for obtaining an estimated temperature of the refrigerant based on the temperature of the switching element;
A torque command value determining unit that obtains the torque command value according to a corrected estimated value obtained by adding a positive offset value to the estimated temperature when the abnormality determining unit makes an abnormality determination;
A vehicle drive motor control apparatus comprising: In the vehicle drive motor control device according to claim 1,
The cooling means is
A pump for circulating the refrigerant;
The abnormality determination unit
First abnormality determining means for determining an abnormality of the cooling means based on the temperature of the refrigerant;
Second abnormality determining means for determining abnormality of the cooling means based on abnormality of the pump;
With
The torque command value determination unit
The vehicle drive motor control device characterized in that the offset value is set to be different when the first abnormality determination means makes an abnormality determination and when the second abnormality determination means makes an abnormality determination. In the vehicle drive motor control device according to claim 2,
A step-up converter that adjusts a DC voltage and outputs it to the inverter;
A step-up converter element temperature detecting means for detecting a temperature of a converter switching element provided in the step-up converter and cooled by the cooling means;
Inverter element temperature detecting means for detecting the temperature of the switching element provided in the inverter;
With
The temperature estimator is
Refrigerant temperature estimating means for locally obtaining the estimated refrigerant temperature based on the detection result of the boost converter element temperature detecting means;
Refrigerant temperature estimation means for locally obtaining the estimated refrigerant temperature based on the detection result of the inverter element temperature detection means;
Means for obtaining a variation value indicating a variation degree of the refrigerant estimated temperature obtained by each refrigerant temperature estimating means;
With
The temperature estimator is
When the first abnormality determining means makes an abnormality determination, the estimated temperature of the refrigerant is obtained based on the maximum value of the refrigerant estimated temperatures obtained by the respective refrigerant temperature estimating means, and the second abnormality determining means is abnormal. When the determination is made, the vehicle drive motor control device is characterized in that an estimated temperature of the refrigerant is obtained based on an average value of the estimated refrigerant temperatures obtained by the respective refrigerant temperature estimating means. In the vehicle drive motor control device according to claim 1 or 2,
A step-up converter that adjusts a DC voltage and outputs it to the inverter;
A step-up converter element temperature detecting means for detecting a temperature of a converter switching element provided in the step-up converter and cooled by the cooling means;
Inverter element temperature detecting means for detecting the temperature of the switching element provided in the inverter;
With
The temperature estimator is
Refrigerant temperature estimating means for locally obtaining the estimated refrigerant temperature based on the detection result of the boost converter element temperature detecting means;
Refrigerant temperature estimation means for locally obtaining the estimated refrigerant temperature based on the detection result of the inverter element temperature detection means;
With
A vehicle drive motor control device characterized in that an estimated temperature of the refrigerant is obtained based on a statistical value with respect to the estimated refrigerant temperature obtained by each refrigerant temperature estimating means. In the vehicle drive motor control device according to claim 1,
A step-up converter that adjusts a DC voltage and outputs it to the inverter;
A step-up converter element temperature detecting means for detecting a temperature of a converter switching element provided in the step-up converter and cooled by the cooling means;
Inverter element temperature detecting means for detecting the temperature of the switching element provided in the inverter;
With
The temperature estimator is
Refrigerant temperature estimating means for locally obtaining the estimated refrigerant temperature based on the detection result of the boost converter element temperature detecting means;
Refrigerant temperature estimation means for locally obtaining the estimated refrigerant temperature based on the detection result of the inverter element temperature detection means;
Means for obtaining a variation value indicating a variation degree of the refrigerant estimated temperature obtained by each refrigerant temperature estimating means;
With
The estimated temperature of the refrigerant is obtained based on the estimated refrigerant temperature obtained from the detection result of the boost converter element temperature detecting means, or the refrigerant temperature is calculated based on the statistical value for the estimated refrigerant temperature obtained by each refrigerant temperature estimating means. Whether to calculate an estimated temperature is determined based on the variation value, and an estimated temperature of the refrigerant is determined according to the determination result. In the vehicle drive motor control device according to claim 5,
The torque command value determination unit
A vehicle drive motor control device, wherein the offset value is set to a different value according to the variation value. In the vehicle drive motor control device according to any one of claims 1 to 6,
The torque command value determination unit
Torque defining means for obtaining the torque command value based on a torque defining relationship defined between a median value for determining the torque command value and the torque command value;
The torque defining means includes
When the abnormality determination unit makes a normal determination, the torque command value is obtained using the temperature of the refrigerant as the median value, and when the abnormality determination unit makes an abnormality determination, the corrected estimated value is used as the median value. A motor control device for driving a vehicle characterized by obtaining a torque command value. In the vehicle drive motor control device according to claim 7,
The control means includes
An initial torque command value determining unit for obtaining an initial value of the torque command value based on a driving operation of the vehicle;
The torque regulation relationship is
The vehicle drive motor control device characterized in that the ratio of the torque command value to the initial value decreases as the median value increases.

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