JP5861590B2 - Temperature detection device - Google Patents

Description

  The present invention relates to a temperature detection device that detects the temperature of a predetermined temperature detection target.

  Conventionally, as can be seen in Patent Document 1 below, a technique for correcting a detected value of a temperature sensor that detects the temperature of a predetermined temperature detection target (for example, a semiconductor switching element) is known. This technology will be described. First, data such as detection values of temperature sensors corresponding to different pairs of temperatures are acquired in a manufacturing process of a product incorporating a temperature sensor. Then, based on the acquired data, correction data for correcting the detection value of the temperature sensor is calculated, and the calculated correction data is stored in a nonvolatile memory mounted on a control board in the product.

  According to such a configuration, the detection value of the temperature sensor can be corrected based on the correction data stored in the nonvolatile memory. Thereby, the fall of the temperature detection precision of temperature detection object can be avoided.

JP 2008-197011 A

  Here, after the product is shipped, the correction data may be lost or the correction data may not be appropriate data. This occurs, for example, when a product fails and a control board on which a nonvolatile memory is mounted is replaced at a product repair shop. In this case, the detection value of the temperature sensor cannot be corrected appropriately, and the temperature detection accuracy of the temperature detection target may be reduced. In order to cope with such a problem, for example, a technique capable of correcting the detection value of the temperature sensor even after the product is shipped is required.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a new temperature detection device that can suppress a decrease in temperature detection accuracy of a temperature detection target by correcting the detection value. .

In order to solve the above problems, the present invention provides a first temperature detection means (Tw #) for detecting the temperature of a predetermined temperature detection target (Sw #: # = p, n), and the temperature of the temperature detection target. Second temperature detecting means (38) for detecting, and a possible range (-b to + b) of the error (Δvs) included in the detected value (Vs) of the second temperature detecting means is the second temperature detecting means (38). The temperature at the place where the first temperature detection means is installed and the second temperature are narrower than the range (-a to + a) that the error (Δvf) included in the detection value (Vf) of the first temperature detection means can take. Correction means (34) for correcting the detection value of the first temperature detection means based on the detection value of the second temperature detection means under a situation where the temperature of the installation location of the detection means is assumed to be the same. It is characterized by providing.

  In the said invention, the range which can take the error contained in the detected value of the said 2nd temperature detection means uses the thing of the said aspect as a 2nd temperature detection means. For this reason, the reliability of the detection value of the second temperature detection means is higher than the reliability of the detection value of the first temperature detection means. On the premise of such a configuration, in the above invention, by providing the correction means, the detection value of the first temperature detection means can be corrected based on the detection value of the second temperature detection means with high reliability. Thereby, the fall of the temperature detection precision of the temperature detection object by a 1st temperature detection means can be suppressed.

  Furthermore, according to the above-described invention, for example, unlike the technique described in Patent Document 1, after the temperature detector is shipped, for example, even when the internal parts of the device are replaced, the correction is performed. The detection value of the first temperature detection means can be corrected by the means.

1 is a system configuration diagram according to a first embodiment. FIG. The block diagram of the temperature detection circuit of the switching element concerning the embodiment. The block diagram of the power card concerning the embodiment. The top view of the control board concerning the embodiment. Side surface sectional drawing of the control board concerning the embodiment. The figure which shows the outline | summary of the error concerning the embodiment. 6 is a flowchart showing a procedure of correction processing according to the embodiment. The figure which shows the temperature characteristic of the resistance value of the thermistor concerning the embodiment. The time chart which shows an example of the correction process concerning the embodiment. The top view of the control board concerning a 2nd embodiment. The flowchart which shows the procedure of the abnormality detection process concerning 3rd Embodiment. The figure which shows the outline | summary of the error concerning 4th Embodiment. 6 is a flowchart showing a procedure of correction processing according to the embodiment. The figure which shows the acquisition timing of the data used for the correction process concerning the embodiment. The block diagram of the power card concerning other embodiment.

(First embodiment)
DESCRIPTION OF EMBODIMENTS Hereinafter, a first embodiment in which a temperature detection device according to the present invention is applied to a vehicle including a rotating machine as an in-vehicle main machine will be described with reference to the drawings.

  FIG. 1 shows a control system according to the present embodiment.

  As shown in the figure, a motor generator 10 as an in-vehicle main machine is connected to an inverter IV, and the inverter IV is connected to a high voltage battery 12 via a converter CV. The converter CV has a function of boosting the voltage of the high voltage battery 12 (for example, “288V”) up to a predetermined voltage (for example, “666V”).

  The inverter IV is configured by connecting three serially connected bodies of a switching element Swp on the upper arm side and a switching element Swn on the lower arm side in parallel. These switching elements Swp and connection points of the switching elements Swn are connected to the U, V, and W phases of the motor generator 10, respectively. Incidentally, in the present embodiment, a voltage control type is used as the switching element Sw # (# = p, n), and more specifically, an insulated gate bipolar transistor (IGBT) is used. Further, a free wheel diode Dw # is connected in antiparallel to each of the switching elements Sw #. Further, although not shown, a temperature sensitive diode for detecting the temperature of the switching element Sw # is provided in the vicinity of the switching element Sw #. The temperature sensitive diode will be described in detail later.

  The control device 14 has a low voltage battery 16 as a power source and is configured mainly with a microcomputer. The control device 14 controls the motor generator 10 by operating the inverter IV and the like via the interface 18. Specifically, the control device 14 turns on and off the switching elements Swp and Swn by transmitting a drive signal to the switching elements Swp and Swn of the inverter IV via the interface 18. Thereby, the control amount of motor generator 10 is controlled to the command value. In the present embodiment, torque is assumed as the control amount of the motor generator 10.

  The upper arm side switching element Swp and the corresponding lower arm side switching element Swn are alternately turned on. Further, the torque command value Tr * is input to the control device 14 from, for example, a host control device that controls the vehicle.

  The interface 18 is a transmission means for exchanging signals between the high voltage system including the high voltage battery 12 and the low voltage system including the low voltage battery 16 while electrically insulating the interface. . In this embodiment, the interface 18 is provided with an optical insulating element (photocoupler). In the present embodiment, the high voltage system corresponds to the first region, and the low voltage system corresponds to the second region.

  Next, a drive circuit and a temperature detection circuit for the switching element Sw # (# = p, n) according to the present embodiment will be described with reference to FIG. In FIG. 2, the interface for driving signal transmission of the switching element Sw # is omitted from the interface 18.

  As shown in the figure, the switching element Sw # is housed in a power card PC and packaged together with a freewheel diode Dw # and a temperature sensitive diode Tw #. The power card PC is a switching module including these elements. Here, the detected value Vf (voltage drop amount) of the temperature sensitive diode Tw # has a negative correlation with the temperature Tf of the switching element Sw #. Incidentally, in the present embodiment, the detected value Vf of the temperature sensitive diode Tw # is a linear expression of the temperature of the switching element Sw #. The temperature sensitive diode Tw # corresponds to first temperature detecting means for detecting the temperature of the switching element Sw # based on the voltage drop amount in itself.

  The switching control terminal (gate) of the switching element Sw # is connected to the integrated circuit 20. The integrated circuit 20 is a dedicated semiconductor device that constitutes a drive circuit for the switching element Sw #, and includes a drive control unit 22. The drive control unit 22 performs an on / off operation of the switching element Sw # based on the drive signal transmitted from the control device 14 or performs a local shutdown process. Here, in the local shutdown process, when it is determined that the detected value Vf of the temperature sensitive diode Tw # (the output value Vcr of the correction circuit 34) is lower than the specified voltage (the temperature of the switching element Sw # is higher than the specified temperature), This is a process for prohibiting the switching element Sw # from being driven, assuming that the switching element Sw # is in an overheated state. Here, the specified temperature is, for example, a lower limit value of the temperature of the switching element Sw # at which the reliability of the switching element Sw # greatly decreases in a short time, and the temperature of the switching element Sw # is the specified temperature. Is set to the detected value Vf of the temperature sensitive diode Tw #. According to the local shutdown process, the switching element Sw # can be quickly turned off, and a situation in which the reliability of the switching element Sw # is significantly reduced due to overheating of the switching element Sw # can be avoided.

  Incidentally, the integrated circuit 20 is provided corresponding to each of the six switching elements Sw # provided in the inverter IV. Further, as shown in FIG. 3, the power card PC includes the Kelvin emitter electrode KE, the sense terminal SE, the gate G of the switching element Sw #, the anode A and the cathode K of the temperature sensitive diode Tw #, and the integrated circuit 20 Are inserted into and connected to the connecting portion of the control board 24 mounted. Here, the Kelvin emitter electrode KE is an electrode having the same potential as the output terminal (emitter) of the switching element Sw #, and the sense terminal SE is a current flowing between the input terminal (collector) of the switching element Sw # and the emitter. This is a terminal for outputting a minute current having a correlation with (collector current).

  Returning to the description of FIG. 2, the integrated circuit 20 further has a function of modulating the detection value Vf of the temperature sensitive diode Tw # into a binary pulse signal. Specifically, the integrated circuit 20 includes a power supply 26, a constant current power supply 28 using the power supply 26 as a power supply source, a PWM comparator 30, and the like.

  The output side of the constant current power supply 28 is connected to the anode of the temperature sensitive diode Tw #, and the cathode of the temperature sensitive diode Tw # is grounded. In the present embodiment, the potential of the grounding part is set to “0”.

  The anode of the temperature sensitive diode Tw # is further connected to the non-inverting input terminal of the PWM comparator 30 via the resistor 32 and the correction circuit 34. The inverting input terminal of the PWM comparator 30 is connected to a carrier generation circuit 36 that outputs a carrier (triangular wave signal tc). In the present embodiment, the PWM comparator 30 and the carrier generation circuit 36 constitute modulation means. The resistor 32 has a function of suppressing transmission of noise to the correction circuit 34, for example. Further, the correction circuit 34 corrects the detection value Vf of the temperature sensitive diode Tw #. The correction circuit 34 will be described in detail later.

  The PWM comparator 30 performs pulse width modulation on the output value Vcr of the correction circuit 34 by comparing the output value Vcr of the correction circuit 34 with the triangular wave signal tc. Accordingly, the output value of the PWM comparator 30 is a ratio of the period of the logic “H” to one cycle of the logic “H” and the logic “L” in accordance with the detection value Vf of the temperature sensitive diode Tw # (duty ratio). Becomes a changing signal.

  Here, since the detected value Vf of the temperature sensitive diode Tw # and the temperature Tf of the switching element Sw # have a negative correlation, the time ratio Duty which is the characteristic value of the output value of the PWM comparator 30 is the detected value Vf. The higher the value, the higher. That is, the duty ratio becomes lower as the temperature Tf of the switching element Sw # becomes higher.

  A thermistor 38 is mounted on the control board in the vicinity of the connection between the power card PC and the control board. One end of the thermistor 38 is connected to a power source 40 having a terminal voltage VH, and the other end is connected to the same grounding part (ground) as the temperature sensitive diode Tw # via a resistor 42. The thermistor 38 has a characteristic that its resistance value decreases as its temperature increases. Therefore, the higher the temperature Tf of the switching element Sw #, the higher the potential at the connection point between the thermistor 38 and the resistor 42 (hereinafter, the detected value Vs of the thermistor 38). That is, the detection value Vs of the thermistor 38 has a positive correlation with the temperature Tf of the switching element Sw #. The detection value Vs of the thermistor 38 is input to the correction circuit 34. In the present embodiment, as the thermistor 38, for example, an NTC thermistor may be used.

  The output terminal of the PWM comparator 30 is connected to the primary side (photodiode) of the photocoupler 44 constituting the interface 18.

  On the other hand, the control device 14 is connected to the secondary side of the photocoupler 44. The controller 14 converts analog data output from the PWM comparator 30 into digital data by software processing, and performs temperature detection processing for detecting the temperature of the switching element Sw # based on the converted digital data. Specifically, the control device 14 calculates the temperature detection value of the switching element Sw # higher as the time ratio Duty of the pulse signal output from the PWM comparator 30 is lower. Specifically, the temperature detection process is performed when, for example, the time ratio Duty and the temperature detection value when the detection value Vf of the temperature sensitive diode Tw # becomes the center characteristic value Vftyp are input with the time ratio Duty as an input. This is done using the associated map. Here, the central characteristic value Vftyp is an average value of detection values of a plurality of temperature-sensitive diodes mass-produced when the temperature Tf of the switching element Sw # becomes a predetermined temperature.

  In addition, when it is determined that the detected temperature value is equal to or higher than the threshold temperature lower than the specified temperature, the control device 14 performs a power saving process for limiting the torque command value Tr *. According to this process, the collector current can be limited, and the switching element Sw # can be protected from overheating.

  Note that the interface 18 connected to the PWM comparator 30, the carrier generation circuit 36, and the PWM comparator 30 is actually one of the six switching elements Sw # provided in the inverter IV in order to reduce the number of components. It is provided for only one. Specifically, only those corresponding to the six switching elements Sw # that are assumed to have the highest temperature are provided. The thermistor 38 is also provided corresponding to only one of the six switching elements Sw # provided in the inverter IV.

  Next, a method for connecting the power card PC to the control board 24 and a method for installing the thermistor 38 on the control board 24 will be described with reference to FIGS. 4 and 5. 4 is a front view of the plate surface of the control board 24, and FIG. 5 is a side sectional view of the control board 24 and the like. Specifically, FIG. 4 is a diagram of the control board 24 viewed from the α direction in FIG.

  As shown in FIG. 4, the control board 24 has a rectangular shape (rectangular shape) in front view of the plate surface. On the control board 24, connection portions skt for connecting the power card PC are provided corresponding to each of the six power card PCs constituting the inverter IV. In the front view of the plate surface of the control board 24, each of the connection portions skt has a rectangular shape, and the connection portions skt are arranged in a line. Further, in the front view of the plate surface of the control board 24, these connection portions skt are provided so as to be separated from each other and in parallel. A through hole for attaching these terminals and the like is formed in the connecting portion skt so that the cathode K, the anode A, the gate G, the sense terminal SE, and the Kelvin emitter electrode KE are arranged in a straight line. Incidentally, each terminal of the power card PC is connected to the connection part skt by soldering. That is, the switching element Sw #, the temperature sensitive diode Tw #, the thermistor 38, and the integrated circuit 20 are mounted on the same control board 24.

  The thermistor 38 is disposed in the vicinity of the connection portion skt on the plate surface of the control board 24. In the present embodiment, the thermistor 38 is disposed in a region sandwiched between the opposed connection portions skt. Since the thermistor 38 is installed in the vicinity of the connection part skt, the thermistor 38 detects the temperature in the vicinity of the land of the connection part skt on the plate surface of the control board 24. Since the land is close to the power card PC, the temperature of the switching element Sw # can be detected based on the voltage drop amount in the thermistor 38. That is, the temperature detection target of the thermistor 38 can be the switching element Sw #.

  Incidentally, the power card PC is cooled by a cooler 46 as shown in FIG. The cooler 46 has a function of cooling the power card PC and the like by circulating a cooling fluid through a flow path formed in the cooler 46.

  Next, correction processing according to the present embodiment will be described.

  This process is executed by the correction circuit 34 in view of the fact that the error Δvf can be included in the detected value Vf of the temperature sensitive diode Tw #. Here, the error Δvf included in the detection value Vf of the temperature sensing diode Tw # is the difference between the actual value Vα and the central characteristic value Vftyp for the detection value Vf of the temperature sensing diode Tw #, as shown in FIG. It means “Vα−Vftyp”. The error Δvf is caused by individual differences of the temperature sensitive diode Tw #. In the present embodiment, the possible range of the error Δvf is “−a to + a” (a> 0). Further, it is assumed that the error Δvf has no temperature dependency of the switching element Sw #. That is, when the detected value Vf of the temperature sensitive diode Tw # includes the error Δvf, the detected value Vf of the temperature sensitive diode Tw # is offset by the error Δvf with respect to the central characteristic value Vftyp. Note that the boundary values “−a, + a” on the high temperature side and the low temperature side within the range that the error can take are fixed values determined according to the specification of the temperature sensing diode Tw #, for example, the temperature sensing diode Tw # This is the guaranteed range for the useful life.

  FIG. 7 shows the procedure of the correction process. This process is repeatedly executed by the correction circuit 34 at a predetermined cycle, for example. Since the correction circuit 34 according to the present embodiment is hardware, the processing shown in FIG. 7 is actually executed by a logic circuit.

  In this series of processing, first, in step S10, it is determined whether or not it is before driving of the switching element Sw # (more specifically, immediately before driving of the switching element Sw #). That is, it is determined whether or not the collector current is flowing through the switching element Sw #. This process is a process for determining whether or not the temperature of the installation location of the thermistor 38 and the temperature of the installation location of the temperature sensitive diode Tw # (temperature Tf of the switching element Sw #) are the same. That is, the situation before the switching element Sw # is driven is a situation in which a sufficient time has passed since the driving of the switching element Sw # was previously stopped. For this reason, various members constituting the inverter IV are in a thermal equilibrium state, and there is a high probability that the temperature at the installation location of the thermistor 38 and the temperature at the installation location of the temperature sensitive diode Tw # are the same.

  If an affirmative determination is made in step S10, the process proceeds to step S12 to determine whether or not the detection value Vs of the thermistor 38 is less than the threshold value Vth. This process is a process for determining whether or not the temperature of the installation location of the thermistor 38 is in a low temperature region, and a process for avoiding a decrease in the correction accuracy of the detection value Vf of the temperature sensitive diode Tw #. It is. Hereinafter, this process will be described.

  In this embodiment, assuming that the detection value Vs of the thermistor 38 is information that accurately indicates the temperature Tf of the switching element Sw #, the detection value Vf of the temperature sensitive diode Tw # is corrected based on the detection value Vs of the thermistor 38. Here, the detected value Vs of the thermistor 38 is information that accurately indicates the temperature Tf of the switching element Sw #. The error Δvs included in the detected value Vs used for correcting the detected value Vf of the temperature sensitive diode Tw #. This is because the possible range “−b to + b” is narrower than the possible range “−a to + a” of the error Δvf included in the detection value Vf of the temperature sensitive diode Tw #. That is, the absolute value “| b |” of the boundary value of the range that can be taken by the error Δvs included in the detection value Vs of the thermistor 38 is the boundary of the range that the error Δvf contained in the detection value Vf of the temperature sensitive diode Tw # can take. This is because the absolute value of the value is smaller than “| a |”. Here, as shown in FIG. 8, the variation in the resistance value R of the thermistor 38 becomes larger as the temperature of the installation location of the thermistor 38 becomes lower. For this reason, the range “−b to + b” that can be taken by the error Δvs included in the detection value Vs of the thermistor 38 becomes wider as the temperature of the installation location of the thermistor 38 is lower. Therefore, in a situation where the thermistor 38 is in a low temperature state, the reliability of the detection value Vs of the thermistor 38 is greatly reduced, and the correction accuracy of the detection value Vf of the temperature sensitive diode Tw # based on the detection value Vs of the thermistor 38 is improved. There is a risk of significant reduction. In order to avoid such a problem, the process of this step is performed.

  Specifically, the threshold value Vth is, for example, the actual installation location of the thermistor 38 when the thermistor 38 in which the error Δvs included in the detection value Vs of the thermistor 38 is the boundary value “b” on the high temperature side is used. May be set to the detection value Vs of the thermistor 38 when the temperature becomes a specified temperature (for example, 0 ° C.).

  Returning to the description of FIG. 7, if an affirmative determination is made in step S12, it is determined that the temperature of the thermistor 38 is in the low temperature region, and the process proceeds to step S13. In step S13, a process for prohibiting the correction process is performed. Specifically, the prohibiting process is performed by prohibiting calculation of a correction value Δcor in step S18 described later.

  On the other hand, if a negative determination is made in step S12, it is determined that the temperature of the installation location of the thermistor 38 is not in the low temperature region, and the process proceeds to step S14. In step S14, the detection value Vf of the temperature sensitive diode Tw # and the detection value Vs of the thermistor 38 are acquired.

  In the subsequent step S16, based on the detection value Vs of the thermistor 38, the central characteristic value Vftyp of the detection value of the temperature sensitive diode Tw # is calculated. Here, the central characteristic value Vftyp can be calculated based on the detection value Vs of the thermistor 38 because the detection value Vs of the thermistor 38 is information that accurately indicates the temperature Tf of the switching element Sw #. This is because it is possible to relate Vs and the central characteristic value Vftyp of the detected value of the temperature sensitive diode Tw #. Incidentally, the center characteristic value Vftyp of the detection value of the temperature sensing diode Tw # is specifically the center of the detection value Vs of the thermistor 38 and the detection value of the temperature sensing diode Tw #. What is necessary is just to calculate using the map with which characteristic value Vftyp was related.

  In the subsequent step S18, the central characteristic value Vftyp of the detected value of the temperature sensitive diode Tw calculated in the process of step S16 is subtracted by the detected value Vf of the temperature sensitive diode Tw # acquired in the process of step S14. A correction value Δcor is calculated. Then, the correction value Δcor is updated by storing the calculated correction value Δcor in a storage unit (for example, a non-volatile memory) provided in the integrated circuit 20.

  On the other hand, if a negative determination is made in step S10, it is determined that the switching element Sw # is being driven, and the process proceeds to step S20. In step S20, the detection value Vf is corrected by adding the correction value Δcor to the detection value Vf of the temperature sensitive diode Tw #.

  In addition, when the process of step S13, S18, S20 is completed, this series of processes are once complete | finished.

  By the way, when the affirmative determination is made in step S12 and the correction value Δcor is not updated, when the switching element Sw # is driven after that, the detected value of the temperature sensitive diode Tw # using the correction value Δcor updated last time. What is necessary is just to correct | amend Vf.

  FIG. 9 shows an example of the update time of the correction value Δcor. Specifically, FIG. 9A shows the transition of whether or not power is supplied from the low voltage battery 16 to the in-vehicle device, and FIG. 9B shows a drive signal output from the control device 14 to the switching element Sw #. FIG. 9C shows the transition of the output signal of the PWM comparator 30 input to the control device 14 via the interface 18.

  In the illustrated example, the vehicle control system is activated at time t1, and power supply from the low-voltage battery 16 to various in-vehicle devices is started. Thereafter, the correction value Δcor is updated at a predetermined timing before time t2 when the torque command value Tr * is input to the control device 14.

  At time t2, a drive signal is output from the control device 14 to the switching element, so that the switching element Sw # starts to be driven. In addition, the detection value Vf of the temperature sensitive diode Tw # is obtained in the correction circuit 34. It is corrected. Then, the output signal of the PWM comparator 30 starts to be input to the control device 14 via the interface 18.

  According to the embodiment described in detail above, the following effects can be obtained.

  (1) Correction processing for correcting the detection value Vf of the temperature sensitive diode Tw # based on the detection value Vs of the thermistor 38 was performed. For this reason, the fall of the temperature detection precision of switching element Sw # can be suppressed suitably. Further, according to the correction process, the detection value Vf of the temperature sensitive diode Tw # can be corrected even after the product is shipped. For this reason, for example, compared with the technique described in the above-mentioned Patent Document 1, even if a problem occurs in the control system due to some factor in the market and the control board 24 is replaced by a vehicle dealer, The detection value Vf can also be corrected. Thereby, the improvement of the exchangeability of the control board 24 can be expected.

  Further, in order to automatically update the correction value Δcor before driving the switching element Sw #, for example, in the product manufacturing process, the process of correcting the detection value of the temperature sensitive diode Tw # for each product is eliminated. Can also be expected.

  (2) The temperature sensitive diode Tw # and the thermistor 38 are mounted on the same control board 24. Therefore, instead of the thermistor 38, for example, a temperature sensor that can detect the temperature of the switching element Sw # and is not mounted on the control board 24 (for example, a sensor that detects the temperature of the cooling fluid flowing through the cooler 46). Compared to the configuration used for the correction process, the number of members for transmitting the detection value of the temperature sensor to the correction circuit 34 can be reduced. Thereby, it is possible to suppress an increase in circuit scale associated with enabling correction processing.

  (3) The thermistor 38 is installed in the vicinity of the connection part skt on the control board 24. Since the vicinity of the connection part skt and the switching element Sw # are close to each other, the temperature of the installation location of the thermistor 38 and the temperature of the switching element Sw # are substantially the same. That is, the thermistor 38 can appropriately detect the temperature of the switching element Sw #.

  (4) When it is determined that the detection value Vf of the thermistor 38 is less than the threshold value Vth, the correction of the detection value Vf is prohibited. For this reason, it can be avoided that the correction accuracy of the detection value Vf of the temperature sensitive diode Tw # is greatly reduced.

  (5) The ground to which the temperature sensitive diode Tw # and the thermistor 38 are connected is the same. According to such a configuration, for example, compared with a configuration in which the ground to which the thermistor 38 is connected is a ground of the low-voltage system, the temperature detection circuit of the switching element Sw # is avoided from being complicated, and in the integrated circuit 20. Means (correction circuit 34) for correcting the detection value Vf of the temperature sensitive diode Tw # can be provided. Therefore, the correction of the detection value Vf of the temperature sensitive diode Tw # can be completed in the integrated circuit 20.

(Second Embodiment)
Hereinafter, the second embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  In the present embodiment, the installation position of the thermistor 38 on the control board 24 is changed.

  FIG. 10 shows the installation position of the thermistor 38. FIG. 10 corresponds to FIG. 4 described above.

  In the present embodiment, the thermistor 38 is installed on a straight line that passes through the connection part skt and is parallel to the connection part skt in the plate surface of the control board 24 in a front view of the plate surface of the control board 24. According to such an installation method, for example, compared to a method in which the thermistor 38 is installed in a region sandwiched between the opposing connection portions skt on the plate surface of the control board 24, the influence of heat released from the power card PC is reduced. It is difficult for the thermistor 38 to receive. For this reason, the probability that the temperature of the installation location of the thermistor 38 and the temperature of the installation location of the temperature sensitive diode Tw # under the situation in which affirmative determination is made in step S10 of FIG. Thereby, the correction accuracy of the detection value Vf of the temperature sensitive diode Tw # can be preferably increased.

(Third embodiment)
Hereinafter, the third embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  In the present embodiment, an abnormality detection process for detecting an abnormality relating to temperature detection by the thermistor 38 is performed. Here, the abnormality includes a short-circuit failure of the thermistor 38, an open failure of the thermistor 38, a disconnection of an electrical path (excluding the thermistor 38 and the resistor 42) from the power supply 40 to the grounded portion, and the resistor 42. At least one of the short-circuit failure and the open failure of the resistor 42 is included.

  FIG. 11 shows the procedure of the abnormality detection process. This process is repeatedly executed by the correction circuit 34 at a predetermined cycle, for example. Since the correction circuit 34 according to the present embodiment is hardware, the processing shown in FIG. 11 is actually executed by a logic circuit.

  In this series of processes, first, in step S22, it is determined whether or not the detection value Vs of the thermistor 38 is higher than “0” and lower than the terminal voltage VH of the power supply 40. This process is a process for determining whether an abnormality relating to temperature detection by the thermistor 38 has occurred. That is, when the disconnection on the power source 40 side from the connection point of the thermistor 38 and the resistor 42 in the electrical path, the open failure of the thermistor 38, or the short-circuit failure of the resistor 42 occurs, the detected value Vs of the thermistor 38 is The value becomes “0” which cannot be obtained when the temperature detection circuit is normal. On the other hand, when a short failure of the thermistor 38 or an open failure of the resistor 42 occurs, the detection value Vs of the thermistor 38 becomes the terminal voltage “VH”, which is a value that cannot be obtained when the temperature detection circuit is normal. For this reason, the presence or absence of the abnormality can be determined by the processing of this step.

  If a negative determination is made in step S22, it is determined that an abnormality relating to temperature detection by the thermistor 38 has occurred, and the process proceeds to step S24. In step S24, the temperature-sensitive diode is added by adding the boundary value “−a” on the high temperature side of the possible range of the error Δvf included in the detected value Vf of the temperature-sensitive diode Tw # to the detected value Vf of the temperature-sensitive diode Tw #. The detection value Vf of Tw # is corrected. This process is provided for fail-safe under circumstances where the correction value Δcor cannot be calculated.

  If an affirmative determination is made in step S22, or if the process in step S24 is completed, the series of processes is temporarily terminated.

  According to the present embodiment described above, even when an abnormality relating to temperature detection by the thermistor 38 occurs, it is avoided that this is underestimated even though the temperature of the switching element Sw # is actually high. it can.

(Fourth embodiment)
Hereinafter, the fourth embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  In the first embodiment, it is assumed that the error Δvf included in the detection value Vf of the temperature sensitive diode Tw # does not have temperature dependency. In this embodiment, as shown in FIG. 12, the error Δvf is assumed to have temperature dependence. Specifically, the error Δvf is a linear expression of the temperature Tf of the switching element Sw #. Note that the actual detection value Vα of the temperature sensitive diode Tw # shown in FIG. 12 is merely an example.

  FIG. 13 shows the procedure of the correction process according to the present embodiment. This process is repeatedly executed by the correction circuit 34 at a predetermined cycle, for example. Since the correction circuit 34 according to the present embodiment is hardware, the processing shown in FIG. 13 is actually executed by a logic circuit. In FIG. 13, the same steps as those shown in FIG. 7 are given the same step numbers for the sake of convenience.

  In this series of processes, when a negative determination is made in step S12, the process proceeds to step S26, and it is determined whether or not it is immediately after the switching element Sw # is stopped. If an affirmative determination is made in step S26, the process proceeds to step S28, and waits until the elapsed time from the timing determined affirmative in step S26 reaches the specified time TA.

  In subsequent step S30, the detection value Vf1 of the temperature sensitive diode Tw # and the detection value Vs1 of the thermistor 38 at the timing when the specified time TA has elapsed are acquired. Then, the detected values Vf1 and Vs1 are updated by storing the acquired detected values Vf1 and Vs1 in a memory. Here, the prescribed time TA is set to a time (fixed time) in which the temperature Tpc of the power card PC and the temperature Tsw of the thermistor 38 are the same, as shown in FIG. FIG. 14 is a diagram illustrating a temperature transition of the power card and the like after the driving of the switching element Sw # is stopped.

  Returning to the description of FIG. 13, in the subsequent step S32, based on the updated detection value Vs1 of the thermistor 38, the central characteristic value Vftyp1 of the detection value of the temperature sensitive diode Tw # is calculated. Then, the central characteristic value Vftyp1 is updated by storing the calculated central characteristic value Vftyp1 in a memory. The reason why the central characteristic value Vftyp1 of the detection value of the temperature sensitive diode Tw # can be calculated based on the updated detection value Vs1 of the thermistor 38 is the same as the reason described in the process of step S16 of FIG. .

  On the other hand, if a negative determination is made in step S26, the process proceeds to step S10. If it is determined in step S10 that the switching element Sw # is not yet driven, the process proceeds to step S34. In step S34, the detection value Vf2 of the temperature sensitive diode Tw # and the detection value Vs2 of the thermistor 38 immediately before driving the switching element Sw # are acquired. Then, the detected values Vf2 and Vs2 are updated by storing the acquired detected values Vf2 and Vs2 in a memory. Note that the detection values Vf2 and Vs2 acquired in this step are sufficiently long since the drive of the switching element Sw # was previously stopped, as shown in FIG. 14, and the power card PC and the thermistor 38 Is a detected value of a situation where the installation location of is in a thermally equilibrium state (illustrated at time t3).

  Returning to the description of FIG. 13, in the subsequent step S36, the central characteristic value Vftyp2 of the detected value of the temperature sensitive diode Tw # is calculated based on the updated detected value Vs2 of the thermistor 38. The reason why the center characteristic value Vftyp2 of the detection value of the temperature sensitive diode Tw # can be calculated based on the updated detection value Vs2 of the thermistor 38 is the same as the reason described in the process of step S16 of FIG. .

  When the processes in steps S32 and S36 are completed, the process proceeds to step S38, and the correction value Δcor is calculated and updated based on the data Vf1, Vf2, Vftyp1, and Vftyp2 updated in the processes in steps S32 and S36. In the present embodiment, as described above, the error Δvf included in the detection value Vf of the temperature sensitive diode Tw # is a linear expression of the temperature Tf of the switching element Sw #. Based on these data Vf1, Vf2, Vftyp1, Vftyp2 corresponding to the temperature Tf, the correction value Δcor is calculated as a linear expression of the detected value Vf of the temperature sensitive diode Tw #.

  When the process of step S13 is completed or when a negative determination is made in step S10, the process proceeds to step S20a, and a correction value Δcor is calculated based on the detected value Vf of the temperature sensitive diode Tw #. The detected value Vf is corrected by adding the calculated correction value Δcor to the detected value Vf of the temperature sensitive diode Tw #.

  In addition, when the process of step S20a and S38 is completed, this series of processes is once complete | finished.

  According to the present embodiment described above, even if the error Δvf included in the detected value Vf of the temperature sensitive diode Tw # has temperature dependence, the detected value Vf of the temperature sensitive diode Tw # is corrected appropriately. be able to.

(Other embodiments)
Each of the above embodiments may be modified as follows.

  The connection method between the power card PC and the control board 24 is not limited to the method shown in FIG. 3 of the first embodiment. For example, as shown in FIG. 15, the control board 24 and the terminals of the power card PC may be connected via a connector 48. Here, the connector 48 includes a conductor 48a as shown in the enlarged view on the left side in the figure, and the conductor 48a is in the normal direction of the contact surface with the terminal of the power card PC (the cathode K is illustrated in the figure). Force F. According to such a configuration, the terminal of the power card PC and the control board 24 can be connected without using solder. As a result, it is possible to improve the exchangeability of the control board 24 and to avoid the replacement of the power card PC when the control board 24 or the like deteriorates over time.

  The “characteristic information” used in the temperature detection process is not limited to a map in which the time ratio Duty of the pulse signal and the temperature detection value are related, but the time ratio Duty is an independent variable and the temperature detection value is a dependent variable. It may be a mathematical formula.

  The carrier used in the “modulation means” is not limited to a triangular wave signal, and may be a sawtooth wave signal, for example.

  In addition, the “modulation means” is not limited to the one that performs pulse width modulation on the detection value of the temperature-sensitive diode. (See JP 2009-171312 A). In this case, for example, in the first embodiment, the pulse signal output from the frequency modulation circuit is transmitted to the control device 14 via the interface 18. And the control apparatus 14 calculates the temperature detection value of a switching element highly, so that the pulse width which is the characteristic value of a pulse signal is short. Here, a map in which the pulse width of the pulse signal and the temperature detection value are related is used as the characteristic information. Even when such a configuration is adopted, application of the present invention is effective because the temperature detection accuracy of the switching element Sw # may be reduced due to replacement of the control board 24 or the like.

  In the fourth embodiment, the error Δvf included in the detected value Vf of the temperature sensitive diode Tw # may be a quadratic expression of the temperature Tf of the switching element Sw #. In this case, for example, on the condition that the temperature of the installation location of the thermistor 38 and the temperature of the installation location of the temperature sensitive diode Tw # are the same, the detection values Vs of the thermistor 38 corresponding to the temperatures of the three different installation locations are different. The correction value Δcor may be calculated based on the detection value Vf of the temperature sensitive diode Tw #.

  In the first embodiment, the absolute values of the boundary value on the high temperature side and the boundary value on the low temperature side are the same among the possible ranges of the error Δvf included in the detection value Vf of the temperature sensitive diode Tw #. However, the present invention is not limited to this, and a temperature sensitive diode having different absolute values may be used. The same applies to the thermistor 38.

  In the first embodiment, even if the interface 18 connected to the PWM comparator 30, the carrier generation circuit 36, and the PWM comparator 30 is provided corresponding to each of the six switching elements Sw # provided in the inverter IV. Good. In this case, the temperature detection values of the six switching elements Sw # are calculated by the temperature detection process in the control device 14.

  In the first embodiment, the correction value Δcor may be calculated when it is determined that the specified time TA has elapsed since the driving of the switching element Sw # was stopped.

  -"Low temperature judgment means" is not restricted to what was illustrated to the said 1st Embodiment. For example, in step S12 of FIG. 7, the detection value Vf of the temperature sensitive diode Tw # may be used instead of the detection value Vs of the thermistor 38.

  The execution subject of the correction process is not limited to the correction circuit 34, and may be the control device 14, for example. In this case, the correction circuit 34 is removed and one end of the resistor 32 is connected to the non-inverting input terminal of the PWM comparator 30 and the detection value of the thermistor 38 is transmitted to the control device 14 (for example, a photocoupler is connected). Provided interface). In such a configuration, the control device 14 calculates the difference between the temperature of the switching element Sw # calculated based on the detection value of the thermistor 38 and the temperature detection value calculated by the temperature detection process, and the calculated difference The temperature detection value calculated in the temperature detection process may be corrected based on the temperature detection process.

  In the second embodiment, the connection portions skt are arranged in one row and six columns in the front view of the plate surface of the control board 24, but the present invention is not limited to this. For example, the connection parts skt may be arranged in 2 rows and 3 columns in a front view of the plate surface of the control board 24.

  In each of the above embodiments, the thermistor is dedicated for detecting the temperature of the switching element Sw #, but is not limited to this, and a member other than the switching element Sw # may be the temperature detection target. Here, the thermistor does not need to be installed near the switching element Sw #. Even in this case, it is considered that the installation location of the thermistor and the temperature of the switching element Sw # are the same before the switching element Sw # is driven. Therefore, the correction value Δcor is calculated based on the detected value of the thermistor. Can do.

  Further, the thermistor is not limited to one and may be plural. In this case, for example, in step S16 of FIG. 7 of the first embodiment, the central characteristic value Vftyp of the detection value of the temperature sensitive diode Tw # may be calculated based on the average value of the detection values of the plurality of thermistors. Since the probability that the average value is close to the central characteristic value Vstyp is higher than that of the single detection value of the thermistor, the calculation accuracy of the correction value Δcor can be expected to be improved.

  The “first temperature detection means” is not limited to a detection value that decreases as the temperature of the temperature detection target increases. In this case, in step S24 of FIG. 11 of the third embodiment, the boundary value on the high temperature side used for correction is “a”.

  Further, the “first temperature detection means” is not limited to the temperature sensitive diode, and the “second temperature detection means” is not limited to the thermistor. In short, if the possible range of error included in the detection value of the second temperature detection means is narrower than the possible range of error included in the detection value of the first temperature detection means, the first and second Other temperature detection means may be adopted as the temperature detection means.

  The ground to which the temperature sensitive diode Tw # and the thermistor 38 are connected is not limited to the same ground. For example, the temperature sensitive diode Tw # may be connected to the ground of the high voltage system and the thermistor 38 may be connected to the ground of the low voltage system. In this case, if the configuration in which the correction circuit 34 is removed from the integrated circuit 20 and the detection value of the thermistor 38 is directly taken into the control device 14 is adopted, the control device 14 can perform the correction process.

  The interface 18 is not limited to the one provided with an optical insulating element such as a photocoupler, and may be provided with a magnetic insulating element (for example, a pulse transformer), for example.

  The “first region” and the “second region” are not limited to those exemplified in the first embodiment. For example, if it is necessary to transmit some temperature information in the low voltage system from the low voltage system side to the high voltage system side, the low voltage system may be the first region and the high voltage system may be the second region.

  The switching element that is the “predetermined temperature detection target” is not limited to the IGBT, but may be, for example, a power MOS field effect transistor. Further, the “predetermined temperature detection target” is not limited to the switching element provided in the inverter IV, and is not limited to the switching element.

  34 ... Correction circuit, 38 ... Thermistor, Sw # (# = p, n) ... Switching element, Tw # ... Temperature sensitive diode.

Claims (8)

First temperature detection means (Tw #) for detecting the temperature of a predetermined temperature detection target (Sw #: # = p, n);
Second temperature detection means (38) for detecting the temperature of the temperature detection target;
With
A possible range (−b to + b) of the error (Δvs) included in the detection value (Vs) of the second temperature detection means is an error (−f to + b) included in the detection value (Vf) of the first temperature detection means. Δvf) is narrower than the possible range (−a to + a),
The range in which the error included in the detection value of the second temperature detection unit can be taken becomes wider as the temperature of the installation location of the second temperature detection unit is lower,
Based on the detection value of the second temperature detection means under a situation where the temperature of the installation location of the first temperature detection means and the temperature of the installation location of the second temperature detection means are assumed to be the same, Correction means (34) for correcting the detection value of the first temperature detection means ;
Low temperature determination means for determining whether or not the temperature of the installation location of the second temperature detection means is in a low temperature region;
A prohibiting means for prohibiting correction by the correcting means based on being determined to be in a low temperature region by the low temperature determining means;
A temperature detecting device comprising:   The temperature detection device according to claim 1, wherein the first temperature detection means and the second temperature detection means are mounted on the same substrate (24).   The temperature detection apparatus according to claim 2, wherein the second temperature detection unit is installed in the vicinity of the temperature detection target.   4. The temperature detection device according to claim 1, wherein each of the first temperature detection unit and the second temperature detection unit is connected to the same ground. 5. An abnormality determination means for determining whether an abnormality relating to temperature detection by the second temperature detection means has occurred;
The correction means is based on the fact that the abnormality determination means has determined that an abnormality has occurred, and the high-temperature side boundary value (−) of the possible range of error included in the detection value of the first temperature detection means. an assembly as claimed in any one of claims 1-4, characterized by correcting the detection value of the temperature detecting means first with a). The temperature detection object, the first temperature detection means, the second temperature detection means, and the correction means are provided in a first region,
Modulation means (30, 36) provided in the first region and modulating the detection value of the first temperature detection means into a pulse signal and outputting the pulse signal;
The second region is provided in a second region that is electrically insulated from the first region, and the output value of the modulation unit, the characteristic value of the output value of the modulation unit, and the temperature of the temperature detection target are related to each other. Calculation means (14) for calculating the temperature of the temperature detection target based on the obtained characteristic information;
Further comprising
Said correcting means, the temperature detection device according to any one of claims 1 to 5, wherein the correcting the detected value of the first temperature sensing means is input to said modulation means. The temperature detection target is a switching element (Sw #),
The switching element and the first temperature detection means constitute a switching module (PC),
The switching module is connected to a connection part (skt) provided on the substrate (24) by its connection terminals (K, A, G, SE, KE),
The connection portions are arranged in a rectangular shape in a plan view of the plate surface of the substrate, and are arranged in parallel and spaced apart from each other.
The second temperature detection means, to any one of claims 1 to 6, characterized in that installed in the region other than the region sandwiched by the connecting portions facing in the plate surface of the substrate The temperature detection device described. 8. The temperature detecting device according to claim 7, wherein the second temperature detecting means is installed on a straight line passing through the connecting portion and parallel to the connecting portion of the plate surface of the substrate.

Images