JP2013242225A - Abnormality discrimination device and abnormality discrimination method for temperature sensor, and power conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an abnormality discrimination device and an abnormality discrimination method for a temperature sensor and a power conversion device capable of improving accuracy in abnormality discrimination and shortening a period till an abnormality is discriminated.SOLUTION: An abnormality discrimination device 13 of a thermistor Th (a temperature sensor) includes a condition setting unit 13a for variably setting at least one of a threshold to be reference of abnormality discrimination in the thermistor Th and a duration time on the basis of at least one of the presence/absence of an actuation state in a power conversion device 10 and an output current Iout (an output value) to be output from the power conversion device 10. An abnormality discrimination unit 13b discriminates whether an abnormality occurs in the thermistor Th or not on the basis of the threshold and duration time set by the condition setting unit 13a. By the configuration, a threshold value for the determination of an abnormality can be relaxed or a duration time can be shortened depending on the presence/absence of an actuation state in the power conversion device 10 and the output current Iout, to thereby shorten a period till an abnormality is discriminated.

Description

  The present invention relates to a temperature sensor abnormality determination device having a temperature sensor and an abnormality determination unit, a temperature sensor abnormality determination method, and a power converter having the abnormality determination device.

  Conventionally, an example of a technique related to an abnormality determination device for a vehicle temperature sensor that can be determined as a sensor abnormality when a temperature sensor indicates a specific detection temperature but does not detect a temperature increase normally (for example, patent document) is disclosed. 1).

  In such an abnormality determination device, an elapsed time in which the temperature detected by the vehicle temperature sensor is continuously included in the temperature region set as the abnormality determination region is measured. Then, when the elapsed time in which the detected temperature is included in the abnormality determination region reaches a predetermined time, it is determined that the vehicle temperature sensor is abnormal.

Japanese Patent Laid-Open No. 10-111182

  By the way, a thermistor is known as an example of a temperature sensor, and the thermistor is an element (resistor) whose electrical resistance value changes with a temperature change of a detection target (oil temperature in Patent Document 1). When detecting the temperature of the detection target provided in the power conversion device using this thermistor, there is the following problem to determine an abnormality associated with a thermistor failure (for example, disconnection or short circuit).

  That is, depending on the thermistor characteristics (including types and individual differences), even when the power converter operates normally, the detected temperature is close to the above certain range, and this is an electrical signal. It may be affected and change across the boundary between normal and abnormal. In order to obtain a stable discrimination result, it is necessary to improve the reliability of the discrimination result by averaging the detected temperatures or setting a long duration until the abnormality is determined. As described above, it takes time to accurately perform the abnormality determination. On the other hand, since there is a technical request for determining an abnormality as early as possible with respect to an abnormality caused by a fatal failure of the thermistor, the technical request is not satisfied in the abnormality determination that takes time.

  This invention is made in view of such a point, and it aims at providing the abnormality determination apparatus of the temperature sensor which can shorten the period until it determines with abnormality, the abnormality determination method, and a power converter device.

  The invention according to claim 1, which has been made to solve the above problems, includes a temperature sensor that detects a temperature of a detection target included in a power converter, a detection value of the temperature sensor, a threshold value, and the detection value as a threshold value. An abnormality determination device for a temperature sensor having an abnormality determination unit for determining whether or not an abnormality has occurred in the temperature sensor using a duration time that is reached, and whether or not the power converter is in an operating state; Based on at least one of output values output from the power converter, a condition setting unit that variably sets at least one of the threshold value serving as a criterion for abnormality determination of the temperature sensor and the duration time is provided. The abnormality determining unit determines whether or not an abnormality has occurred in the temperature sensor based on the threshold value and the duration set by the condition setting unit. And butterflies.

  According to this configuration, each quantity of the first threshold value and the first duration time is set by the condition setting unit based on at least one of the presence / absence of the operating state of the power converter and the output value output from the power converter. Is done. Based on the threshold value and the duration time set in this way, the abnormality determination unit determines whether or not an abnormality has occurred in the temperature sensor. The presence / absence of the operating state of the power conversion device and the output value may have a correlation with the temperature of the detection target provided in the power conversion device. Therefore, it is possible to loosen (low or high) the threshold value for judging an abnormality based on the presence or absence of the operating state of the power conversion device and the output value using this correlation, or to shorten the duration time, so that it is judged as abnormal. Can be shortened.

  The “detection target” is arbitrary as long as it is a component of the power conversion device. For example, a semiconductor element (including a switching element), a transformer, a diode, a case, and the like are applicable. The “temperature sensor” is arbitrary as long as it can detect the temperature of the object to be detected. For example, a thermistor is applicable. “Abnormal” includes failures such as disconnection and short circuit.

  According to a second aspect of the present invention, the temperature sensor has a characteristic of indicating a low temperature when a detection value increases, and the abnormality determination unit is configured such that the detection value indicates a low temperature value larger than the threshold value. It is characterized by determining that a disconnection abnormality has occurred. According to this configuration, the present invention can be suitably applied to an abnormality determination device having a disconnection abnormality threshold on the low temperature side.

  According to a third aspect of the present invention, the duration includes a first duration and a second duration shorter than the first duration, and the condition setting unit is operated when the power converter is operating. Is set to the second duration, and the first duration is set when the power converter is not operating. According to this configuration, when operating, it can be assumed that the temperature of the power conversion device is higher than when not operating, so if the reference value indicating a low temperature is reached, there is a possibility that it is abnormal. Even if the duration is shortened, it is possible to appropriately determine the abnormality, and early detection can be realized.

  According to a fourth aspect of the present invention, the duration includes a second duration and a third duration shorter than the second duration, and the condition setting unit is configured such that the output value is less than the first reference value. The third duration is set when the output value is high, and the second duration is set when the output value is lower than the first reference value. According to this configuration, when the output value is high, it can be assumed that the temperature of the power conversion device is high. Therefore, if the reference value indicating the low temperature is reached, there is a high possibility that it is abnormal, and the duration time is shortened. However, it is possible to appropriately determine the abnormality and realize early detection.

  According to a fifth aspect of the present invention, the duration includes a third duration and a fourth duration shorter than the third duration, and the condition setting unit has the output value smaller than the second reference value. The fourth duration is set when the output is high, and the third duration is set when the output value is less than or equal to the second reference value. According to this configuration, when the output value is high, it can be assumed that the temperature of the power conversion device is high. Therefore, if the threshold value set on the low temperature side has been reached, there is a high possibility that it is abnormal, and the duration time is reduced. Even if it is shortened, it is possible to properly determine an abnormality, and early detection can be realized.

  The invention according to claim 6 is set so that the first duration is the longest and the fourth duration is the shortest among the first duration to the fourth duration. It is characterized by that. According to this configuration, if the reference value indicating the low temperature is reached or the threshold value set on the low temperature side is reached, there is a high possibility of an abnormality, and even if the duration is shortened, the abnormality can be properly determined. Early detection can be realized.

  According to a seventh aspect of the present invention, the threshold includes a first threshold and a second threshold that is on a higher temperature side of the detection area of the temperature sensor than the first threshold, and the condition setting unit includes the power The second threshold value is set when the conversion device is operating, and the first threshold value is set when the power conversion device is not operating. According to this configuration, when operating, it can be assumed that the temperature of the power conversion device is higher than when not operating, and therefore it may be abnormal if the threshold set on the low temperature side is reached. Even if the threshold value is lowered, it is possible to appropriately determine abnormality, and early detection can be realized.

  According to an eighth aspect of the present invention, the threshold includes a second threshold and a third threshold that is on a higher temperature side of the detection region of the temperature sensor than the second threshold, and the condition setting unit includes the output The third threshold value is set when the value is higher than the first reference value, and the second threshold value is set when the output value is less than or equal to the first reference value. According to this configuration, when the output value is high, it can be assumed that the temperature of the power conversion device is high. Therefore, if the threshold value set on the low temperature side is reached, the possibility of an abnormality is high, and the duration time is shortened. Even in this case, it is possible to appropriately determine the abnormality and realize early detection.

  The invention according to claim 9 is characterized in that the threshold value includes a third threshold value and a fourth threshold value that is on a higher temperature side of the detection region of the temperature sensor than the third threshold value, and the condition setting unit includes the output The fourth threshold value is set when the value is higher than the second reference value, and the third threshold value is set when the output value is less than or equal to the second reference value. According to this configuration, when the output value is high, it can be assumed that the temperature of the power conversion device is high. Therefore, if the threshold value set on the low temperature side has been reached, there is a high possibility that it is abnormal, and the duration time is reduced. Even if it is shortened, it is possible to properly determine an abnormality, and early detection can be realized.

  According to a tenth aspect of the present invention, the first threshold value is set to be the lowest temperature side and the fourth threshold value is set to the highest temperature side from the first threshold value to the fourth threshold value. It is characterized by being. According to this configuration, if the reference value indicating the low temperature is reached, or if the threshold value set on the low temperature side is reached, there is a high possibility that it is abnormal. Early detection can be realized.

  Invention of Claim 11 has the abnormality determination apparatus of the temperature sensor as described in any one of Claims 1-10, and the electric power conversion part containing the switching element which performs switching, The said temperature sensor is The switching element is disposed at a position where it can be raised and lowered in accordance with the temperature rise and fall of the switching element. According to this configuration, the switching element is a component whose temperature rises and falls in accordance with the presence / absence of the operating state of the power conversion device and the output value output from the power conversion device. The effect of Claim 1 can be obtained suitably.

  The invention according to claim 12 is a temperature sensor for detecting a temperature of a detection target provided in the power converter, a detection value of the temperature sensor, a threshold value, and a duration time during which the detection value reaches the threshold value. In the abnormality determination method of the temperature sensor having an abnormality determination unit that determines whether or not an abnormality has occurred in the temperature sensor using the presence / absence of the operating state of the power converter and the output output from the power converter A condition setting step for variably setting at least one of the threshold value serving as a criterion for abnormality determination of the temperature sensor and the duration based on at least one of the values; and the threshold value set by the condition setting step And an abnormality determination step of determining whether an abnormality has occurred in the temperature sensor based on the duration time.

  According to this configuration, each quantity of the threshold value and the duration time is set by the condition setting step based on at least one of the presence / absence of the operating state of the power converter and the output value output from the power converter. Based on the threshold value and duration time set in this manner, in the abnormality determination step, it is determined whether or not an abnormality has occurred in the temperature sensor. The presence / absence of the operating state of the power conversion device and the output value may have a correlation with the temperature of the detection target provided in the power conversion device. Therefore, using this correlation, it is possible to lower the threshold value for determining an abnormality based on the presence / absence of the operating state of the power conversion device and the output value, and to shorten the duration time, so the time period until an abnormality is determined is shortened. can do.

It is a schematic diagram which shows the structural example of a power converter device. It is a flowchart which shows the example of a procedure of abnormality determination processing. It is a time chart which shows a time-dependent change, such as a detected value (temperature). It is a graph which shows the example of a characteristic of a thermistor. It is a flowchart which shows the example of a procedure of the abnormality determination process of 2nd Embodiment. It is a time chart which shows a time-dependent change of the detected value (temperature) etc. of 2nd Embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. Note that unless otherwise specified, “connecting” means electrically connecting. Each figure shows elements necessary for explaining the present invention, and does not necessarily show all actual elements. When referring to directions such as up, down, left and right, the description in the drawings is used as a reference.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. 1 includes a converter 11, an inverter 12 indicated by a two-dot chain line, capacitors C1 and C2 indicated by a two-dot chain line, an abnormality determination device 13, a thermistor Th, and the like. The abnormality determination device 13 corresponds to a “temperature sensor abnormality determination device”, and the thermistor Th corresponds to a “temperature sensor”. In the first embodiment, the thermistor Th in which the coefficient k in the expression “ΔR = kΔT” indicating the relationship between the resistance value ΔR and the temperature ΔT is a negative value is used. The power source E corresponds to, for example, a fuel cell or a chargeable / dischargeable battery.

  The converter 11 is a so-called “DC-DC converter”, and corresponds to a “power converter”. The converter 11 has a function of converting the DC input voltage Vin supplied from the power source E into an output voltage Vout (corresponding to a target value; Vout ≠ Vin). In general, since the output voltage Vout is maintained at a substantially target value, the output current (an output current Iout described later) varies depending on the load condition on the output side. Since a well-known converter can be applied to the converter 11, illustration and description relating to a specific configuration example are omitted.

  In this embodiment, the thermistor Th is provided to detect the temperature of the switching element Q (semiconductor element) included in the converter 11. The number of the thermistors Th is arbitrary. About converter 11 which has a plurality of switching elements Q, it may be provided corresponding to any one or two switching elements Q, and may be provided corresponding to every switching element Q. The arrangement form of the thermistor Th with respect to the switching element Q may be contact / non-contact or built-in / non-built-in. In short, what is necessary is just to be able to detect the temperature of the switching element Q. Depending on the configuration of the converter 11, a reflux diode D is connected in parallel to the switching element Q as indicated by a two-dot chain line.

  Capacitor C1 is connected to the input side of converter 11, and capacitor C2 is connected to the output side of converter 11. Each capacitor has a function of smoothing voltage fluctuation (pulsating flow) and stabilizing the DC voltage value. Whether or not one or both of these capacitors C1 and C2 is provided in the power converter 10 is arbitrary. In addition to the form of connection as shown in the figure, a capacitor having a corresponding capacity may be built in the converter 11 or the inverter 12. A capacitor may be used instead of (or in combination with) the capacitor.

  The inverter 12 corresponds to a “power converter”, and whether or not the power converter 10 is provided is arbitrary. The inverter 12 has a function of inputting the output voltage Vout (input power) supplied from the converter 11 and converting it into output power Pout supplied to the output device 20. Instead of the output power Pout, an output voltage or an output current may be applied. In other words, the conversion control is performed so that one or more of the output power Pout, the output voltage, and the output current become the target value. Since a known inverter 12 can be applied, illustrations and descriptions relating to specific configuration examples are omitted.

  The abnormality determination device 13 includes a condition setting unit 13a and an abnormality determination unit 13b. The abnormality determination device 13 may be configured by software or hardware as long as each function of the condition setting unit 13a and the abnormality determination unit 13b can be realized. The condition setting unit 13a has a function of variably setting at least one of threshold values (V1 to V4) serving as a criterion for abnormality determination of the thermistor Th and durations (T1 to T4). In this embodiment, the threshold value V1 corresponds to a “first threshold value”, the threshold value V2 corresponds to a “second threshold value”, the threshold value V3 corresponds to a “third threshold value”, and the threshold value V4 corresponds to a “fourth threshold value”. To do. Similarly, the duration T1 corresponds to “first duration”, the duration T2 corresponds to “second duration”, the duration T3 corresponds to “third duration”, and the duration T4 is “ This corresponds to the “fourth duration”.

  Specifically, while the power conversion device 10 (the converter 11 in this embodiment) is in operation, one of the second to fourth threshold values and the second to fourth duration times is set according to the output current Iout. On the other hand, when the power converter is not operating, the first threshold value and the first duration time are set.

  The setting by the condition setting unit 13a is performed on a recording medium provided in the abnormality determination device 13. As the recording medium, any medium capable of recording threshold values (V1 to V4), duration times (T1 to T4), and the like can be applied. For example, one or more of a memory such as a RAM, a flash memory (including an SSD), a hard disk, an optical disk (including a magneto-optical disk, etc.), a flexible disk, and the like are applicable.

  The abnormality determination unit 13b has a function of determining whether an abnormality (that is, disconnection, short circuit, or the like) has occurred in the thermistor Th. As shown in FIG. 4, when the thermistor Th is short-circuited, the detected value Vth corresponding to the detected temperature becomes 0 [V], indicating that it is out of the actual operating temperature range, so that it can be easily determined. Outside the actual use temperature range, a short-circuit region where the detection value Vth is smaller than VL and a disconnection region where the detection value Vth is larger than the threshold value V4 are applicable. On the other hand, when the thermistor Th is disconnected, it is difficult to discriminate due to its characteristics. Specifically, based on the threshold value and duration set by the condition setting unit 13a, whether or not the detection value Vth detected by the thermistor Th has reached the threshold value, the threshold arrival period Ty (the threshold value has been reached). The period is determined based on whether or not the duration is longer than the duration. The “abnormality” of the thermistor Th includes a state close to a disconnection or a short circuit.

  The thermistor Th exhibits the characteristics shown in FIG. 4 in relation to the detected value and the temperature. Specifically, the higher the detected value, the lower the temperature, and the lower the detected value, the higher the value.

  Further, the following relationship can be assumed between the output current Iout of the power converter 10 and the temperature indicated by the thermistor Th. That is, it can be assumed that as the output current Iout of the power converter 10 increases, the heat due to the loss generated in the switching element Q and the like also increases. Therefore, when the output current is high, it can be assumed that the temperature detected by the thermistor Th around the switching element Q of the power converter 10 is high.

  In the present embodiment, the thermistor is pulled up so that a predetermined high voltage is applied at the time of disconnection. The threshold value for determining the disconnection is set on the low temperature side (high voltage side) of the detection value of the thermistor, and there is a range that overlaps the actual use temperature range, so that the output current Iout of the power converter 10 is small Even if the detected value is high, it is difficult to determine whether the detected high voltage value indicates a low temperature or indicates a disconnection abnormality. Therefore, at least one of a threshold value that can reliably determine that the temperature is not low and a determination time that exceeds the threshold value to ensure that the low temperature is not indicated are required. On the other hand, if the output current Iout of the power conversion device 10 increases, it can be assumed that the temperature detected by the thermistor Th is high, and thus the detected value cannot indicate a low temperature. Therefore, if the threshold set on the low temperature side (high voltage side) has been reached, there is a high possibility of a disconnection abnormality, and even if the threshold is lowered or the duration is shortened and an abnormality is judged, an erroneous judgment is made. There is nothing. Therefore, early detection of disconnection can be realized by lowering the threshold or shortening the duration as the output current increases.

  Hereinafter, in the power conversion device 10 configured as described above, a specific procedure example of abnormality determination processing executed by the abnormality determination device 13 will be described with reference to the flowchart of FIG. Steps S10 to S12 and steps S20 to S23 shown in FIG. 2 correspond to the condition setting unit 13a and the condition setting process. Similarly, steps S30 to S34 correspond to the abnormality determination unit 13b and the abnormality determination step.

  In this embodiment, a current lower than the first reference current Is1 (corresponding to the first reference value) (that is, Iout ≦ Is1) is applied to the “low output” shown in FIG. As the “medium output”, a current exceeding the first reference current Is1 and equal to or less than the second reference current Is2 (corresponding to the second reference value) (that is, Is1 <Iout ≦ Is2) is applied. Specific quantities relating to the first reference current Is1 and the second reference current Is2, the set threshold value Vx, and the set duration time Tx can be arbitrarily set individually. The set threshold value Vx corresponds to any one of threshold values V1, V2, V3, and V4 (where V1> V2> V3> V4). The set duration Tx corresponds to one of durations T1, T2, T3, and T4 (where T1> T2> T3> T4). Actually, appropriate numerical values are set in accordance with the configuration of the converter 11 and the characteristics of the thermistor Th. The threshold reaching period Ty is a period (time) during which the output current Iout continuously reaches the set threshold Vx. The threshold reaching period Ty may be initialized (Ty = 0) in advance when the power is turned on or reset, or may be set to a constant value depending on the temperature when the power is turned on.

  The abnormality determination process shown in FIG. 2 is repeatedly executed. First, it is determined whether or not the converter 11 is operating (power conversion) [step S10]. If the converter 11 is not converting (NO), the threshold value V1 and the duration time T1 are set [step S20], and the process proceeds to step S30 described later.

  If the converter 11 is in operation, it is determined whether or not the output current Iout is low [step S11]. If the output current Iout is low (Iout ≦ Is1; YES), a threshold value V2 (V2 <V1) smaller than the threshold value V1 and a duration time T2 (T2 <T1) shorter than the duration time T1 are set respectively [ Step S21], the process proceeds to Step S30 described later.

  If the output current Iout is not low output (Iout> Is1; NO in step S11), it is determined whether or not the output current Iout is medium output [step S12]. If the output current Iout is medium output (Is1 <Iout ≦ Is2; YES), a threshold V3 (V3 <V2) smaller than the threshold V2 and a duration T3 (T3 <T2) shorter than the duration T2 are set. [Step S22], the process proceeds to Step S30 described later. On the other hand, if the output current Iout is high (Is2 <Iout), a threshold V4 (V4 <V3) smaller than the threshold V3 and a duration T4 (T4 <T3) shorter than the duration T3 are set. [Step S23], the process proceeds to Step S30 described later.

  In step S30, it is determined whether or not an abnormality has occurred in the thermistor Th. Specifically, the determination is made based on whether or not the threshold reaching period Ty has continued for a set duration Tx (T1, T2, T3, or T4). If the threshold reaching period Ty continues for the set duration Tx or longer (Ty ≧ Tx; YES), the abnormality of the thermistor Th is notified [step S32] and returned (including the end, and so on). .

  If the threshold reaching period Ty has not reached the set duration Tx (Ty <Tx; NO), it is determined whether or not the detection value Vth has reached the set threshold Vx (V1, V2, V3 or V4) [ Step S31]. In this embodiment, since the disconnection failure of the thermistor Th is regarded as an abnormality, the determination is made based on whether or not the detection value Vth is equal to or greater than the set threshold value Vx (Vth ≧ Vx). If the detected value Vth is greater than or equal to the set threshold value Vx (YES), the threshold reaching period Ty is increased [step S33] and the process returns. The increase value of the threshold reaching period Ty in step S33 is arbitrary. For example, it corresponds to a repetition period of abnormality determination processing, a predetermined value (corresponding to a predetermined time), or the like.

  On the other hand, if the detection value Vth is below the set threshold value Vx (NO in step S31), the thermistor Th functions normally, and the process returns as it is. If necessary, as indicated by a two-dot chain line, the threshold reaching period Ty may be initialized (Ty = 0) [Step S34], and the process may be returned. For example, if the threshold arrival period Ty is short and the detection value Vth exceeds the set threshold Vx, the detection value Vth may be erroneously detected.

  An example of determining the abnormality of the thermistor Th in the power conversion device 10 configured as described above will be described with reference to FIG. In FIG. 3, the horizontal axis represents time, and the vertical axis represents the change over time in the output voltage Vout and the abnormality determination unit 13b. A detection characteristic line Lx indicated by a two-dot chain line indicates an actual temperature change. The threshold characteristic line Lth shows the change over time of the set threshold value Vx. Each change of the detection characteristic lines Lx, Lr3, Lr4 and the threshold characteristic line Lth is merely an example shown for convenience of explanation.

  A detection characteristic line Lr4 indicated by a solid line in FIG. 3 is an example in which the period during which the detection value Vth is equal to or greater than the threshold value V4 reaches the duration T4 when the output current Iout is high. Hereinafter, a control example based on a change in the detection characteristic line Lr4 will be described.

  The period from time t0 to time t1 is a period during which the power conversion device 10 is not operating (NO in step S10 of FIG. 2). During the period, the threshold value V1 and the duration time T1 are set (step S20 in FIG. 2). For this setting, since the detection value Vth is below the threshold value V1, the thermistor Th is normal. Therefore, the abnormality determination unit 13b does not determine that there is an abnormality (NO in step S30 in FIG. 2).

  From time t1 to time t2, the output current Iout is low (YES in step S11 in FIG. 2), and the threshold value V2 and the duration T2 are set during this period (step S21 in FIG. 2). For this setting, since the detection value Vth is below the threshold value V2, the thermistor Th is normal. Therefore, the abnormality determination unit 13b does not determine that there is an abnormality (NO in step S30 in FIG. 2).

  From time t2 to time t5, the output current Iout becomes medium output (YES in step S12 in FIG. 2), and the threshold value V3 and duration T3 are set during this period (step S21 in FIG. 2). For this setting, since the detection value Vth is below the threshold value V3, the thermistor Th is normal. Therefore, the abnormality determination unit 13b does not determine that there is an abnormality (NO in step S30 in FIG. 2).

  After the time t5, the output current Iout becomes a high output (NO in step S12 in FIG. 2), and the threshold value V4 and the duration T4 are set during the period (step S21 in FIG. 2). With respect to this setting, the detection value Vth becomes equal to or greater than the threshold value V4 from time t5 and the threshold value reaching period Ty increases (step S33 in FIG. 2). T4) is reached. Therefore, it is determined that an abnormality has occurred in the thermistor Th and notified (YES in step S30 in FIG. 2, step S32).

  As described above, by using the threshold value V4 and the duration T4 that are varied based on the output current Iout, it is possible to determine the abnormality of the thermistor Th at the time t6 when the duration T4 elapses from the time t5. As a comparative example, it is assumed that the threshold value V1 and the duration time T1 are not changed by the output current Iout. In the example of FIG. 3, the detected value Vth exceeds the threshold value V1, and the time T1 elapses from the time t7 is the time t8 (> t6), and the threshold value V4 and the duration time T4 that are varied based on the output current Iout are set. By using it, it can be seen that an abnormality can be judged early.

  In addition, the detection characteristic line Lr3 indicated by the alternate long and short dash line in FIG. 3 uses the threshold V3 and the duration T3 that are varied based on the output current Iout of the medium output, thereby continuing the period in which the detection value Vth is equal to or greater than the threshold V3. In this example, the time T3 is reached. Also in this example, it is possible to determine abnormality of the thermistor Th at time t4 (<t8). As in the case of the detection characteristic line Lr4 described above, it can be seen that the abnormality can be determined early. Although not shown, an example in which the period during which the detection value Vth is equal to or greater than the threshold value V2 reaches the duration time T2 using the threshold value V3 and the duration time T3 that are varied based on the low output current Iout is similarly early. Abnormality judgment is possible.

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

  (1) In the abnormality determination device 13 of the thermistor Th (temperature sensor), the thermistor Th is based on at least one of the presence / absence of the operating state of the power converter 10 and the output current Iout (output value) output from the power converter 10. A condition setting unit 13a that variably sets at least one of threshold values V1 to V4 serving as a criterion for abnormality determination and durations T1 to T4. The abnormality determination unit 13b is set by the condition setting unit 13a. Based on the thresholds V1 to V4 and the durations T1 to T4, it is determined whether or not an abnormality has occurred in the thermistor Th (see FIGS. 1 to 3). According to this configuration, it is possible to loosen the threshold value for determining an abnormality based on the presence / absence of the operating state of the power conversion device 10 and the output current Iout, or to shorten the duration time. can do. “To loosen the threshold value” is to lower or increase the threshold value according to, for example, the coefficient k (positive or negative).

  (2) The thermistor Th has a characteristic that indicates a low temperature when the detection value Vth increases (see FIG. 4), and the abnormality determination unit 13b indicates a low temperature value at which the detection value Vth is greater than the threshold values V1 to V4. In some cases, it is determined that an abnormality has occurred (see FIG. 2). According to this configuration, the present invention can be suitably applied to the abnormality determination device 13 having the threshold values V1 to V4 on the low temperature side.

  (3) A duration T1 (first duration) and a duration T2 (second duration) shorter than the duration T1 are provided, and the condition setting unit 13a continues when the power converter 10 is operating. The time T2 is set, and when the power conversion device 10 is not operating (stopped), the duration T1 is set (see FIGS. 2 and 3). According to this configuration, when operating, it can be assumed that the temperature of the power conversion device 10 is higher than when not operating. Therefore, if the reference value indicating a low temperature is reached, there is a possibility that it is abnormal. Therefore, even if the duration time is shortened, it is possible to appropriately determine an abnormality and realize early detection.

  (4) A duration T2 (second duration) and a duration T3 (third duration) shorter than the duration T2 are provided, and the condition setting unit 13a determines that the output current Iout is the first reference current Is1 (first reference). When the output current Iout is equal to or less than the first reference current Is1, the duration T2 is set (see FIGS. 2 and 3). According to this configuration, when the output current Iout (output value) is high, it can be assumed that the temperature of the power converter 10 is high. Therefore, if the reference value indicating a low temperature is reached, there is a high possibility of an abnormality. Even if the duration time is shortened, the abnormality can be properly determined, and early detection can be realized.

  (5) A duration T3 (third duration) and a duration T4 (fourth duration) shorter than the duration T3 are provided, and the condition setting unit 13a sets the output current Iout to the second reference current Is2 (second reference). When the output current Iout is less than or equal to the second reference current Is2, the duration T3 is set (see FIGS. 2 and 3). According to this configuration, when the output current Iout (output value) is high, it can be assumed that the temperature of the power converter 10 is high. Therefore, if the reference value indicating a low temperature is reached, there is a high possibility of an abnormality. Even if the duration time is shortened, the abnormality can be properly determined, and early detection can be realized.

  (6) Among the durations T1 to T4, the duration T1 (first duration) is set to be the longest and the duration T4 (fourth duration) is set to be the shortest ( (See FIGS. 2 and 3). According to this configuration, if the reference value indicating the low temperature is reached or the threshold value set on the low temperature side is reached, there is a high possibility of an abnormality, and even if the duration is shortened, the abnormality can be properly determined. Early detection can be realized.

  (7) The threshold value V1 (first threshold value) and the threshold value V2 (second threshold value) that is higher than the threshold value V1 in the detection region of the thermistor Vh are provided, and the condition setting unit 13a operates the power conversion device 10 In this case, the threshold value V2 is set, and when the power conversion apparatus 10 is not operating (stopped), the threshold value V1 is set (see FIGS. 2 and 3). According to this configuration, when operating, it can be assumed that the temperature of the power conversion device 10 is higher than when not operating. Therefore, if the reference value indicating a low temperature is reached, there is a possibility that it is abnormal. Therefore, even if the duration time is shortened, it is possible to appropriately determine an abnormality and realize early detection.

  (8) A threshold value V2 (second threshold value) and a threshold value V3 (third threshold value) that is higher than the threshold value V2 in the detection region of the thermistor Vh are provided, and the condition setting unit 13a has the output current Iout as the first reference current Is1. The threshold V3 is set when higher than (first reference value), and the threshold V2 is set when the output current Iout is equal to or lower than the first reference current Is1 (see FIGS. 2 and 3). According to this configuration, when the output current Iout is high, it can be assumed that the temperature of the power conversion device 10 is high. Therefore, if the reference value indicating the low temperature is reached, there is a high possibility that it is abnormal, and the threshold value is low. Even in this case, it is possible to appropriately determine the abnormality and realize early detection.

  (9) A threshold value V3 (third threshold value) and a threshold value V4 (fourth threshold value) that is higher than the threshold value V3 in the detection region of the thermistor Vh are provided, and the condition setting unit 13a has the output current Iout as the second reference current Is2. The threshold V4 is set when higher than (second reference value), and the threshold V3 is set when the output current Iout is equal to or lower than the second reference current Is2 (see FIGS. 2 and 3). According to this configuration, when the output current Iout (output value) is high, it can be assumed that the temperature of the power conversion device 10 is high. Therefore, if the threshold value set on the low temperature side is reached, there is a possibility that it is abnormal. Therefore, even if the duration time is shortened, it is possible to appropriately determine an abnormality and realize early detection.

  (10) Among the threshold values V1 to V4, the threshold value V1 (first threshold value) is set to be the lowest temperature side, and the threshold value V4 (fourth threshold value) is set to be the highest temperature side. (See FIGS. 2 and 3). According to this configuration, if the reference value indicating the low temperature is reached, or if the threshold value set on the low temperature side is reached, there is a high possibility that it is abnormal. Early detection can be realized.

  (11) It has the thermistor Th abnormality determination device 13 and the converter 11 (power conversion unit) including the switching element Q that performs switching, and the thermistor Th can be raised and lowered as the temperature of the switching element Q rises and falls. It was set as the structure arrange | positioned in the position (refer FIG. 1). According to this configuration, the switching element Q is a component whose temperature rises and falls according to the presence / absence of the operating state of the power conversion device 10 and the output current Iout output from the power conversion device 10. Therefore, it is possible to lower the threshold value for determining an abnormality based on the presence / absence of the operating state of the power conversion device 10 and the output current Iout or to shorten the duration time, and thus it is possible to shorten the period until the abnormality is determined. .

  (12) Thermistor Th that detects the temperature of the detection target provided in the power conversion device 10, the detection value Vth of the thermistor Th, the threshold values V1 to V4, and the duration that the detection value Vth has reached the threshold values V1 to V4 In the abnormality determination method of the thermistor Th having an abnormality determination unit 13b that determines whether or not an abnormality has occurred in the thermistor Th using T1 to T4, the presence / absence of the operating state of the power converter 10 and the power converter 10 Based on at least one of the output currents Iout to be output, at least one of threshold values V1 to V4 (threshold values) and a continuation time T1 to T4 (duration time), which is a criterion for determining the abnormality of the thermistor Th, is variably set. An abnormality occurs in the thermistor Th based on the condition setting step, the threshold values V1 to V4 set by the condition setting step, and the durations T1 to T4. And an abnormality determination step for determining whether or not the operation is performed (see FIGS. 1 and 3). According to this configuration, it is possible to lower the threshold value for determining an abnormality based on the presence / absence of the operating state of the power conversion device 10 and the output current Iout, or to shorten the duration time, so that the period until the abnormality is determined is shortened. can do.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. 5 and 6. The second embodiment differs from the first embodiment in that the threshold is not changed and only the duration is changed due to the difference in output current. Therefore, differences from the first embodiment will be described, and the rest of the configuration is the same as that of the first embodiment, and thus description thereof will be omitted.

  As described above, the threshold for determining disconnection is set on the low temperature side (high voltage side) of the detection value Vth detected by the thermistor Th. When the output current Iout of the power converter 10 is small and heat generation is small, it is difficult to determine whether the detected high voltage value indicates a low temperature or a disconnection abnormality even if the detection value Vth is high. . At this time, if the output current Iout of the power conversion device 10 increases even if the threshold value for determining whether or not it is disconnected is the same as the output current Iout of the power conversion device 10, the temperature detected by the thermistor Th is high. Since it can be assumed, the detection value Vth cannot indicate a low temperature. Therefore, if the threshold set on the low temperature side (high voltage side) has been reached, there is a high possibility of a disconnection abnormality. There is no. Therefore, it is possible to realize early detection of disconnection by shortening the duration as the output current Iout increases.

  FIG. 5 shows specific abnormality determination processing. First, it is determined whether or not the converter 11 is operating (power conversion) [step S10]. If the converter 11 is not in operation (NO), the duration T1 is set [step S20], and the process proceeds to step S30. Step S30 is the same as that in the first embodiment, and a description thereof will be omitted.

  If the converter 11 is converting, it is determined whether or not the output current Iout is low (ie, Iout ≦ Is1) [step S11]. If the output current Iout is low (YES), a duration T2 (T2 <T1) shorter than the duration T1 is set [Step S21], and the process proceeds to Step S30.

  If the output current Iout is not low (Iout> Is1; NO in step S11), a duration T3 (T3 <T2) shorter than the duration T2 is set [step S22], and the process proceeds to step S30.

  In this way, by using the durations T1 to T3 that are variably set according to the output current Iout, as shown in FIG. 6, if the duration is T1, the abnormality determination that takes until time t13 is set to the duration T2. For example, it is possible at time t12 (<t13), and it is possible at time t11 (<t12) if the duration time T3 is set. Even if it does in this way, the effect similar to 1st Embodiment can be acquired.

[Other Embodiments]
Although the form for implementing this invention was demonstrated according to 1st Embodiment and 2nd Embodiment above, this invention is not limited to the said form at all. In other words, various forms can be implemented without departing from the scope of the present invention. For example, the following forms may be realized.

  In the first and second embodiments described above, the thermistor Th in which the coefficient k in the equation “ΔR = kΔT” indicating the relationship between the resistance value ΔR and the temperature ΔT is a negative value is applied as a “temperature sensor” (FIG. 3). Instead of this form, a thermistor Th having a positive coefficient k may be applied. The same applies when other detection elements other than the thermistor Th are applied as the temperature sensor.

  In the first embodiment and the second embodiment described above, the switching element Q provided in the converter 11 is applied as a “detection target” that the thermistor Th detects the temperature (see FIG. 1). Instead of (or in combination with) this form, other switching elements excluding the switching element Q, semiconductor elements excluding the switching elements (including integrated circuits such as LSIs and diodes, for example), transformers, cases (housings) ) May be applied to one or more of the above. In other words, any component of the power conversion device 10 is optional. Regardless of the object to be detected, the processing is performed as shown in FIGS. Therefore, the same effect as the first embodiment and the second embodiment described above can be obtained.

  In the first embodiment and the second embodiment described above, the condition setting unit 13a is configured to set a threshold and a duration based on the output current Iout output from the converter 11 (steps S10 to S12 in FIG. 2 are performed). reference). Instead of (or in combination with) this configuration, a threshold value or duration may be set based on one or more of output power (corresponding to a power value) output from the converter 11 or output voltage. In this case, one or more of the reference power value and the reference voltage value are applied as the reference value for setting the threshold and the duration. There may be one or more reference values. In other words, an appropriate quantity is set according to the configuration of the converter 11 (for example, the type of switching element Q, the output voltage Vout, etc.), the type and characteristics of the thermistor Th, and the like.

  Furthermore, it is good also as a structure which adds the efficiency (eta) of the converter 11 as a judgment element, and sets a threshold value or duration. That is, in step S11, it is determined whether or not the power is low and the voltage is low (Vout ≦ V1, Pout ≦ P1), and in step S12, whether or not the power is medium and the voltage is determined (V1 <Vout ≦ V2). , P1 <Pout ≦ P2).

  When a power value other than the direct current is applied, the output current Iout shown in FIG. 1 may be read as the output power Pout or the output voltage Vout. When the efficiency η is applied, the ratio of the output power Pout and the input power value Pin of the converter 11 shown in FIG. 1 (that is, η = Pout / Pin) may be applied in a configuration in which the inequality relationship is reversed. In these cases, the determination in steps S10 and S31 in FIG. 2 is performed based on the read power value or efficiency η. In any configuration, the abnormality determination is performed based on the quantity corresponding to the state of the converter 11, so that the accuracy of the abnormality determination is improved and the period until the abnormality is determined can be shortened. Therefore, the same effect as the first embodiment and the second embodiment described above can be obtained.

  In the first embodiment and the second embodiment described above, only the converter 11 is applied as the “power converter” (see the solid line in FIG. 1). Instead of (or in combination with) this form, only the inverter 12 may be applied (see the two-dot chain line in FIG. 1), or both the converter 11 and the inverter 12 may be applied. It is arbitrary how the power conversion device 10 is configured according to the output device 20. The inverter 12 has a switching element Q, a diode D, and the like as in the converter 11. Therefore, since abnormality determination is performed based on the quantity corresponding to the state of the inverter 12, the accuracy of abnormality determination is improved, and it is determined that the abnormality is detected. Can be shortened. Therefore, the same effect as the first embodiment and the second embodiment described above can be obtained.

  In the first and second embodiments described above, the first reference voltage Vs1 is applied as the “first reference value”, and the second reference voltage Vs2 is applied as the “second reference value” (step S11 in FIG. 2). , S12). Instead of this form, any number of reference values (reference voltages) of three or more may be applied. In other words, the optimum number of reference values according to the characteristics of the thermistor Th is applied. By this application, the accuracy of abnormality determination is further improved, and the period until it is determined as abnormal can be further shortened. The same applies when reference power or reference current is applied instead of the reference voltage. Therefore, the same effect as the first embodiment and the second embodiment described above can be obtained.

  In the first embodiment and the second embodiment described above, it is determined whether or not the converter 11 is operating (power conversion), and the threshold value and the duration or the duration is determined depending on whether or not the converter 11 is operating (power conversion). However, even if the threshold value and the duration time are not changed depending on whether or not the converter 11 is operating (power conversion), the same value may be used for at least one of the threshold value and the duration time. Good. In this case, at least one of the threshold value and the duration time is changed depending on whether the converter 11 is in operation and the output current Iout is the output current (output value).

  In addition, when the converter 11 is in operation, at least one of the threshold value and the duration time may be changed based only on whether the converter 11 is in operation (power conversion) without changing the threshold value and the duration time.

10 Power Converter 11 Converter (Power Converter)
12 Inverter (Power converter)
13 Abnormality determination device (temperature sensor abnormality determination device)
13a Condition setting unit 13b Abnormality determination unit Th Thermistor (temperature sensor)
V1, V2, V3, V4 threshold T1, T2, T3, T4 duration

Claims (12)

An abnormality occurs in the temperature sensor using a temperature sensor that detects a temperature of a detection object included in the power converter, and a detection value of the temperature sensor, a threshold value, and a duration time during which the detection value reaches the threshold value. In the temperature sensor abnormality determination device having an abnormality determination unit for determining whether or not
Based on at least one of the presence / absence of the operating state of the power converter and the output value output from the power converter, at least one of the threshold value serving as a criterion for abnormality determination of the temperature sensor and the duration is variable. Has a condition setting part to set,
The abnormality determination unit determines whether or not an abnormality has occurred in the temperature sensor based on the threshold value and the duration set by the condition setting unit. apparatus. The temperature sensor has a characteristic of indicating a low temperature when the detection value increases,
The temperature sensor abnormality determination device according to claim 1, wherein the abnormality determination unit determines that an abnormality has occurred when the detected value indicates a low temperature value greater than the threshold value. The duration comprises a first duration and a second duration shorter than the first duration,
The condition setting unit sets the second duration when the power conversion device is operating, and sets the first duration when the power conversion device is not operating. The abnormality determination device for a temperature sensor according to claim 1 or 2. The duration comprises a second duration and a third duration shorter than the second duration,
The condition setting unit sets the third duration when the output value is higher than the first reference value, and sets the second duration when the output value is lower than the first reference value. The temperature sensor abnormality determination device according to any one of claims 1 to 3, wherein the temperature sensor abnormality determination device is set. The duration comprises a third duration and a fourth duration shorter than the third duration,
The condition setting unit sets the fourth duration when the output value is higher than the second reference value, and sets the third duration when the output value is equal to or less than the second reference value. The temperature sensor abnormality determination device according to any one of claims 1 to 4, wherein:   Of the first duration to the fourth duration, the first duration is set to be the longest and the fourth duration is set to be the shortest. The abnormality determination device for a temperature sensor according to claim 5. The threshold includes a first threshold and a second threshold that is on a higher temperature side of the detection region of the temperature sensor than the first threshold,
The condition setting unit sets the second threshold when the power converter is operating, and sets the first threshold when the power converter is not operating. The temperature sensor abnormality determination device according to any one of claims 1 to 6. The threshold value includes a second threshold value and a third threshold value that is on a higher temperature side of the detection region of the temperature sensor than the second threshold value,
The condition setting unit sets the third threshold when the output value is higher than the first reference value, and sets the second threshold when the output value is less than or equal to the first reference value. The temperature sensor abnormality determination device according to claim 1, wherein the temperature sensor abnormality determination device is characterized in that: The threshold includes a third threshold and a fourth threshold that is on the higher temperature side of the detection region of the temperature sensor than the third threshold,
The condition setting unit sets the fourth threshold value when the output value is higher than the second reference value, and sets the third threshold value when the output value is equal to or less than the second reference value. The abnormality determination device for a temperature sensor according to any one of claims 1 to 8.   The first threshold value is set to be the lowest temperature side from the first threshold value to the fourth threshold value, and the fourth threshold value is set to be the highest temperature side. Item 10. The temperature sensor abnormality determination device according to Item 9. The temperature sensor abnormality determination device according to any one of claims 1 to 10, and a power conversion unit including a switching element that performs switching,
The power conversion device according to claim 1, wherein the temperature sensor is arranged at a position where the temperature sensor can be raised and lowered in accordance with the temperature rise and fall of the switching element. An abnormality occurs in the temperature sensor using a temperature sensor that detects a temperature of a detection object included in the power converter, and a detection value of the temperature sensor, a threshold value, and a duration time during which the detection value reaches the threshold value. In the abnormality determination method of the temperature sensor having an abnormality determination unit for determining whether or not
Based on at least one of the presence / absence of the operating state of the power converter and the output value output from the power converter, at least one of the threshold value serving as a criterion for abnormality determination of the temperature sensor and the duration is variable. A condition setting process to be set,
An abnormality determination step of determining whether or not an abnormality has occurred in the temperature sensor based on the threshold value set in the condition setting step and the duration time;
An abnormality determination method for a temperature sensor, comprising:

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