Method and device for determining the temperature calibration characteristic curve of a semiconductor component appertaining to power electronics

Abstract

The temperature calibration characteristic curve of a semiconductor component can be readily determined by interconnecting the power connections of the semiconductor component with a first current source for a load current, a second current source for a measurement current and a voltmeter for measuring the voltage drop across the power connections. Furthermore, the semiconductor component is connected to a data processing system and heated by the dissipated power at time intervals when the first current source is connected, and the voltage drop across the power or auxiliary connections is measured when the first current source disconnected and the second current source is connected between the intervals after a time duration determined by the thermal main time constant of the semiconductor component. The temperature of the semiconductor component is separately measured and the temperature calibration characteristic curve is obtained by correlating the measured temperature with the voltage drop.

Claims

1. An improved method for determining a temperature calibration characteristic curve of a power semiconductor component of power electronics using a data processing system, comprising the steps of: interconnecting power connections of the power semiconductor component with a first current source adapted to provide a load current, with a second current source adapted to provide a measurement current, and with a voltmeter adapted to measure a voltage drop either across the power connections or across auxiliary connections connected to said power connections, heating the power semiconductor component during specified time intervals by dissipating power provided by the first current source in the power semiconductor component, measuring the voltage drop across the power connections or across said auxiliary connections between said specified time intervals with the first current source disconnected and the second current source connected, and simultaneously measuring a temperature of the power semiconductor component using at least one temperature sensor connected to the data processing system after a period of time determined by a main thermal time constant of the power semiconductor component has elapsed since the last specified time interval, as a measured temperature value corresponding to a voltage drop of the power semiconductor component, and providing the simultaneously measured voltage drop and temperature to the data processing system, said data processing system assigning the temperature of the at least one temperature sensor to the corresponding voltage drop, and a temperature calibration characteristic curve of the power semiconductor component using a plurality of measured voltage drops and a plurality of corresponding simultaneously measured temperatures.

2. The method of claim 1, wherein the specified time intervals determine heating of the power semiconductor component and the period of time between the specified time intervals determines a cool-down and the measurement of the value representing the temperature, wherein heating of the power semiconductor component occurs in stages, wherein the period of time for the cool-down is sufficiently long so that the temperature is higher than the temperature of a measurement point resulting from a preceding interval.

3. The method of claim 1, wherein a chip and a heat sink of the power semiconductor component during cool-down between the specified time intervals after an integer multiple of the thermal main time constant are largely at an identical temperature level, at which time the voltage drop across the power connections or the auxiliary connections and the temperature are measured.

4. The method of claim 3, wherein the integer multiple of the thermal main constant is four times the thermal main constant.

5. The method of claim 3, wherein the integer multiple of the thermal main constant is more than four times the thermal main constant.

6. The method of claim 1, wherein the current of the first current source is 25% to 100% of a rated current of the semiconductor component.

7. An improved device for determining a temperature calibration characteristic curve of a power semiconductor component of power electronics, comprising: a first current source adapted to be connected to the power semiconductor component to supply a load current, a second current source adapted to be connected to the power semiconductor component to supply a measurement current, a voltmeter adapted to be connected across power connections or across auxiliary connections connected to the power connections to measure a voltage drop across the power connections or across the auxiliary connections, and a data processing system configured to: a) connect the first current source to supply a load current from the first current source at during specified time intervals to heat the power semiconductor component by dissipating power in the power semiconductor component, b) disconnect the first current source and connect the second current source to supply a measurement current to the power semiconductor component, c) after a period of time determined by a thermal main time constant of the power semiconductor component has elapsed since disconnecting the first current source, measure the voltage drop across the power connections or across the auxiliary connections, between the specified time intervals with the first current source disconnected and the second current source connected, as a voltage drop corresponding to a simultaneously measured temperature of the power semiconductor component and simultaneously measure a temperature of the power semiconductor component using at least one temperature sensor coupled to the power semiconductor component and connected to the data processing system, and d) form a temperature calibration characteristic curve of the power semiconductor component using a plurality of the measured voltage drops and the corresponding simultaneously measured temperatures of the power semiconductor component produced by dissipating power in the power semiconductor component.

8. The device of claim 7, wherein the power semiconductor component is an insulated gate bipolar transistor, a power MOSFET, a power JFET, a thyristor, a diac, a triac or a diode.

Description

(1) In the drawings:

(2) FIG. 1 shows a device for active determination of the temperature calibration characteristic curve of an insulated gate bipolar transistor as a semiconductor component appertaining to power electronics and

(3) FIG. 2 shows a curve of a measurement.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(4) In the exemplary embodiment below a method and a device for determining the temperature calibration characteristic curve of an insulated gate bipolar transistor as a semiconductor component 3 appertaining to power electronics together will be explained in greater detail.

(5) A device for determining the temperature calibration characteristic curve of an insulated gate bipolar transistor 3 as semiconductor component 3 appertaining to power electronics essentially consists of a first current source 1 for a load current I.sub.load, a second current source 2 for a measurement current I.sub.meas, a voltmeter V for measuring the voltage U.sub.CE falling over the collector-emitter path, a data processing system and a temperature sensor coupled to the bipolar transistor 3.

(6) FIG. 1 shows a device for active determination of the temperature calibration characteristic curve of an insulated gate bipolar transistor D as a semiconductor component 3 appertaining to power electronics in a basic diagram.

(7) The insulated gate bipolar transistor 3 will be referred to below as a power semiconductor 3.

(8) The collector-emitter path of the power semiconductor 3 is interconnected with the first power source 1 for a current I.sub.load less than or equal to the rated current, the second power source 2 for a measurement current I.sub.meas, the voltmeter V for measuring the voltage U.sub.CE falling via the collector-emitter path and the data processing system for controlling the measurement, storage of the measurement data and evaluation.

(9) The data processing system is further connected to the temperature sensor. The collector and the emitter are the power connections or the power and the auxiliary connections of the power semiconductor 3.

(10) The data processing system and the temperature sensor are not shown in FIG. 1.

(11) The power semiconductor 3 will be heated up via its power loss at specific and predetermined intervals with the first current source 1 connected. The current I.sub.load of the first current source 1 in this case is 50% of the rated current of the power semiconductor 3 for example.

(12) The process is controlled by means of the data processing system.

(13) With the first current source 1 switched off and the second current source 2 connected the voltage U.sub.CE dropping via the collector-emitter path is measured between the intervals after a period of time t.sub.meas defined by the thermal main constant of the power semiconductor as values representing the temperature. At the same time the temperature will be measured by a temperature sensor coupled to the power semiconductor 3. The values will be stored on a data processing system and processed so that the values, after a linear approximation for example, form the calibration characteristic curve of the power semiconductor 3.

(14) FIG. 2 shows a curve of a measurement in a basic diagram.

(15) The intervals t.sub.on determine the heating up and the time t.sub.fail and t.sub.meas between the intervals t.sub.on determine the cooling down and measurement. The heating up takes place in stages, wherein the current I.sub.load flows.

(16) The periods of time t.sub.fall and t.sub.meas are long enough for the temperature of the measurement point i+1 to be greater than the temperature of the measurement point i resulting from the predecessor interval t.sub.on.

(17) To this end FIG. 2 shows the temperature curve T.sub.vj for the chip temperature, wherein vj stands for virtual junction, and the temperature curve T.sub.C stands for the housing temperature of the power semiconductor 3, wherein C stands for case.

(18) The chip of the power semiconductor 3 and the heatsink of the power semiconductor 3 are largely at the same temperature level during the cooling down between the intervals after five times the thermal main time constant, wherein especially in this case the measurement is undertaken via the voltage (measurement points i and i+1) falling over the collector-emitter path.

(19) The values and the associated temperatures, after a linear approximation in the data processing system, form the calibration characteristic curve of the power semiconductor 3 for example.