JP7302432B2 - Semiconductor device control device - Google Patents

Description

The technology disclosed in the present specification relates to a control device for a semiconductor device.

Patent Literature 1 discloses an elevator control device as an example of a semiconductor element control device. This control device includes a protection unit that changes normal operation to protective operation when it is determined that a semiconductor element in the inverter has reached the end of its life, and a determination unit that determines the life from changes in the temperature of heat generated by the semiconductor element in the inverter. Prepare.

Japanese Patent No. 4896992

In the above-described control device, the estimated value of the temperature change width of heat generated by the semiconductor element, which differs for each car traveling pattern, is registered in advance in association with the car traveling pattern, and based on the traveling command, the heat generation corresponding to the car traveling pattern is registered. The number of times heat is generated in the width of temperature change is accumulated. Then, based on the accumulated number of times of heat generation, the determination unit determines whether the semiconductor element has reached the end of its life. In general, it is known that a brittle member such as a semiconductor element is affected by deterioration of the semiconductor element not only by temperature change but also by the temperature history such as the maximum temperature and the minimum temperature experienced so far. However, in the control device described above, since the threshold value for life determination is constant regardless of the maximum or minimum temperature experienced by the semiconductor element, there is a risk of failing to accurately determine the degree of deterioration. The present specification provides a technique that solves or at least reduces such problems and can accurately determine the deterioration of a semiconductor device.

A semiconductor device control apparatus disclosed in the present specification includes an element temperature sensor that detects the temperature of a semiconductor element, a protection unit that performs a predetermined protective operation on the semiconductor element, and a temperature detected by the element temperature sensor. and a judgment unit for judging whether or not protective operation by the protection unit is necessary by comparing the upper limit threshold value, and the judgment unit lowers the upper limit threshold value when the temperature detected by the element temperature sensor falls below the lower limit threshold value. .

The control device described above monitors the temperature of the semiconductor element with a temperature sensor that detects the temperature of the semiconductor element, and lowers the upper threshold when the lowest temperature of the semiconductor element falls below the lower threshold. Therefore, the difference between the maximum temperature and the minimum temperature of the semiconductor element can be controlled so as not to exceed a certain value. As a result, it is possible to appropriately protect the semiconductor element by considering the temperature history actually experienced by the semiconductor element.

1 shows the configuration of a control device 10 of an embodiment. 3 shows processing related to the protection operation of the semiconductor element 2 by the processing device 14. FIG. FIG. 4 shows a schematic diagram of obtaining the minimum value Tmin and the maximum value Tmax in a predetermined period;

A control device 10 of an embodiment will be described with reference to the drawings. The control device 10 of this embodiment is a device for controlling the operation of the semiconductor element 2 . The semiconductor element 2 is a power semiconductor element, and may be, for example, a switching element of a power conversion circuit such as a DC/DC converter or an inverter. In the following description, a single semiconductor element 2 will be described as a representative, but the control device 10 of this embodiment can be similarly applied to various circuits having a plurality of semiconductor elements. Although not particularly limited, the control device 10 of the present embodiment can be suitably employed in, for example, a power conversion circuit of an electric vehicle (including a hybrid vehicle and a fuel cell vehicle).

As shown in FIG. 1, the control device 10 includes an element temperature sensor 12, a processing device 14, and a drive circuit 24. As shown in FIG. The element temperature sensor 12 is positioned near the semiconductor element 2 or built in the semiconductor element 2 to detect the temperature of the semiconductor element 2 . Here, the specific configuration of the element temperature sensor 12 is not particularly limited. The element temperature sensor 12 may be any sensor that can directly or indirectly measure the temperature of the semiconductor element 2 . For example, the element temperature sensor 12 may be a water temperature sensor that detects the temperature of cooling water used to cool the semiconductor element 2 .

The processing device 14 is connected to the element temperature sensor 12 and monitors the temperature detected by the element temperature sensor 12 , that is, the temperature of the semiconductor element 2 . The processor 14 outputs a predetermined protection signal to the drive circuit 24 when the temperature detected by the element temperature sensor 12 exceeds a predetermined upper threshold.

A drive circuit 24 is connected to the gate of the semiconductor element 2 . The drive circuit 24 intermittently turns on and off the semiconductor element 2 based on a PWM signal PWM1 input from an external control device. The drive circuit 24 is also connected to the processor 14 . When the drive circuit 24 receives the protection signal described above from the processing device 14, the drive circuit 24 performs a predetermined protection operation regardless of the PWM signal PWM1. The protection operation here is not particularly limited, but prohibits or limits the ON operation of the semiconductor element 2 in order to suppress the temperature rise of the semiconductor element 2 .

The processing device 14 includes an output section 16 , a memory 18 , a determination section 20 and a protection section 22 . As described above, the temperature detected by the element temperature sensor 12 is input to the processing device 14 . The processor 14 cumulatively records the input sensed temperatures in the memory 18 . As a result, the history of temperatures that the semiconductor element 2 has experienced so far is recorded in the memory 18 as temperature history data. Although the content of the temperature history data is not particularly limited, it is preferable that at least the maximum value Tmax and the minimum value Tmin, which will be described later, are recorded.

The processing device 14 can output the temperature history data recorded in the memory 18 to the outside via the output unit 16 . The output unit 16 is, for example, wired or wireless communication means. The temperature history data may be output at any time, for example, in response to an external request. For example, if it is used in an automobile, the temperature history data may be referenced by an operator during repair or maintenance of the automobile. Alternatively, temperature history data may be output automatically according to a predetermined timing or schedule. For example, when it is used in an automobile, the temperature history data may be automatically sent to an external server when the automobile starts or reaches a predetermined travel distance.

The determination unit 20 and the protection unit 22 are provided to perform the protection operation of the semiconductor element 2 described above. The determination unit 20 determines whether or not the protection operation is necessary by comparing the temperature detected by the element temperature sensor 12 and the upper limit threshold value registered in the memory 18 . Then, when the determination unit 20 determines that the protection operation is necessary, the protection unit 22 outputs a protection signal to the drive circuit 24 . As a result, the protection operation described above is performed in the drive circuit 24 .

Referring to FIG. 2, the processing related to the protection operation of the semiconductor element 2 by the processing device 14 will be described. First, in step S<b>30 , the determination unit 20 acquires the temperature T of the semiconductor element 2 from the element temperature sensor 12 . Next, in step S32, the determination unit 20 compares the acquired temperature T of the semiconductor element 2 with the pre-stored minimum value Tmin. The minimum value Tmin indicates the lowest temperature among the temperatures that the semiconductor device 2 has experienced so far. When determining that the obtained temperature T of the semiconductor element 2 is less than the minimum value Tmin (YES in S32), the determination unit 20 proceeds to the process of step S42. On the other hand, if the determination unit 20 determines that the obtained temperature T of the semiconductor element 2 is equal to or higher than the minimum value Tmin (NO in S32), the process proceeds to step S34.

In step S<b>42 , the memory 18 records the obtained temperature T of the semiconductor element 2 and the minimum value Tmin as new temperature information experienced by the semiconductor element 2 . Next, the processing device 14 proceeds to the processing of step S34.

In step S34, the determination unit 20 compares the acquired temperature T of the semiconductor element 2 with a pre-registered maximum value Tmax. The maximum value Tmax refers to the highest temperature that the semiconductor device 2 has ever experienced. When determining that the obtained temperature T of the semiconductor element 2 exceeds the maximum value Tmax (YES in S34), the determination unit 20 proceeds to the process of step S44. On the other hand, if the determination unit 20 determines that the obtained temperature T of the semiconductor element 2 is equal to or lower than the maximum value Tmax (NO in S34), the process proceeds to step S36.

In step S<b>44 , the memory 18 records the obtained temperature T of the semiconductor element 2 and the maximum value Tmax as new temperature information experienced by the semiconductor element 2 . Next, the processing device 14 proceeds to the processing of step S36. Through the steps up to this point, as illustrated in FIG. 3, regarding the temperature history of the semiconductor element 2 during a predetermined period, the temperature T1 at time t1 is set to the minimum value Tmin, the temperature T2 at time t2 is set to the maximum value Tmax, and the memory 18 stored in The predetermined period referred to here may be determined in terms of time as shown in FIG. 3, or may be determined in terms of travel distance in the case of an automobile, for example.

In step S36, the determination unit 20 calculates the temperature difference between the maximum value Tmax and the minimum value Tmin recorded in the memory 18, and compares the temperature difference with a pre-registered threshold value ΔT. The determination unit 20 determines that protection or warning is necessary when the temperature difference between the maximum value Tmax and the minimum value Tmin exceeds the threshold value ΔT. In this case, the process proceeds to step S<b>46 , and the determination unit 20 instructs the protection unit 22 to protect the semiconductor element 2 . The protection unit 22 performs a protection operation on the semiconductor element 2 together with the drive circuit 24 in accordance with the command from the determination unit 20 . Alternatively, the determination unit 20 may issue a warning to the user's attention via a user interface (not shown). After that, the processing device 14 proceeds to the processing of step S38. On the other hand, if the temperature difference between the maximum value Tmax and the minimum value Tmin is equal to or less than ΔT (NO in S36), step S46 is skipped and the process proceeds directly to step S38.

At step S<b>38 , the determination unit 20 compares the minimum value Tmin recorded in the memory 18 with the lower limit threshold Tth<b>1 registered in advance in the memory 18 . If the determination unit 20 determines that the minimum value Tmin is less than the lower limit threshold value Tth1 (YES in S38), the process proceeds to step S48.

In step S48, the determination unit 20 determines that the upper threshold Tth2 should be lowered, and updates the current upper threshold Tth2 registered in the memory 18 to a new lower threshold Tth2. The amount of decrease at this time is determined from the minimum value Tmin and the lower limit threshold value Tth1, and is set to be equal to or greater than the difference between the lower limit threshold value Tth1 and the minimum value Tmin. That is, when the minimum value Tmin of the semiconductor element 2 falls below the lower limit threshold value Tth1, the upper limit threshold value Tth2 is lowered by at least the lower temperature range. Therefore, the difference between the maximum and minimum temperatures experienced by the semiconductor device 2 can be controlled so as not to exceed a certain value. As a result, the semiconductor element 2 can be appropriately protected in consideration of the temperature history actually experienced by the semiconductor element 2 . Here, the upper threshold value Tth2 may be reset in a predetermined period and changed to an initial value.

The processing device 14 repeats the above-described series of processes, that is, the process flow shown in FIG. 2 as one cycle at predetermined intervals. As a result, the upper threshold value Tth2 registered in the memory 18 is updated according to the minimum value Tmin experienced by the semiconductor device 2 . As described above, the processing device 14 causes the determination unit 20 and the protection unit 22 to output a protection signal to the drive circuit 24 when the temperature detected by the element temperature sensor 12 exceeds the upper threshold value Tth2 registered in the memory 18. output to execute the protection operation for the semiconductor element 2 . As a result, the semiconductor element 2 can be appropriately protected in consideration of the temperature history actually experienced by the semiconductor element 2 .

Although several specific examples have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or drawings exhibit technical usefulness alone or in various combinations.

2: Semiconductor device 10: Semiconductor device control device 12: Device temperature sensor 14: Processing device 16: Output unit 18: Memory 20: Determination unit 22: Protection unit 24: Drive circuit Tmin: Minimum value Tmax: Maximum value Tth1: Lower limit threshold Tth2: upper threshold

Claims (1)

A control device for a semiconductor device,
an element temperature sensor that detects the temperature of the semiconductor element;
a protection unit for performing a predetermined protection operation on the semiconductor element;
a determination unit that determines whether the protection operation by the protection unit is necessary by comparing the temperature detected by the element temperature sensor with an upper limit threshold;
with
The determining unit lowers the upper threshold when the temperature detected by the element temperature sensor falls below the lower threshold.
Control device.

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