JP2005003601A - Hybrid sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a temperature simultaneously with detection of a current flowing in a conductor to be measured in the electrically noncontact state without increasing the number of components or increasing the labor for incorporation. <P>SOLUTION: In this hybrid sensor, an output resistance 5 is connected to a Rogowski coil 3 arranged close to a semiconductor chip 10 as the conductor to be measured in parallel with the Rogowski coil 3 through a lead wire 4, and a first current detection circuit 6 for detecting a flowing current in the semiconductor chip 10 from the voltage of the output resistance 5 is provided, to thereby constitute a current sensor. The sensor is also equipped with a first temperature detection circuit 12 for detecting the temperature of the semiconductor chip 10 from the current and the voltage by making a current flow in the Rogowski coil 3, and a first circuit switching device 11 for connecting the first temperature detection circuit 12 to the Rogowski coil 3 instead of the output resistance 5 and the first current detection circuit 6. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hybrid sensor that detects the temperature of a conductor to be measured using a current sensor that measures a current value from a magnetic field generated by a current flowing through the conductor to be measured.
[0002]
[Prior art]
There is a Rogowski coil as a magnetic field measurement current sensor capable of measuring a current by measuring a magnetic field generated by a current flowing through a conductor to be measured (see, for example, Patent Document 1).
FIG. 5 is a configuration diagram showing a general configuration for detecting a current flowing through a conductor to be measured by a Rogowski coil, and is a first conductor made of a nonmagnetic conductor having a closed loop shape cut out. 1, a second conductor 2 that is also a nonmagnetic conductor is insulated from the first conductor 1 and wound, and the first conductor 1 and the second conductor 2 are connected in series to form the Rogowski coil 3. The conductor to be measured 7 is arranged so as to be surrounded by the Rogowski coil 3. When a current flows through the conductor to be measured 7, a magnetic field is generated around the conductor. Therefore, the current flowing through the conductor to be measured 7 can be obtained by circular integration. For this purpose, a first current detection circuit 6 that connects the output resistor 5 in parallel with the Rogowski coil 3 at the tip of the lead wire 4 connected to the Rogowski coil 3 and circulates and integrates the voltage of the output resistor 5 is provided.
[0003]
With such a configuration, the current can be measured in an electrically non-contact state with the conductor 7 to be measured, and the Rogowski coil 3 has a notch so that the current path is not opened. However, it has the feature that it can be worn.
Such a feature is convenient for measuring the current flowing through the semiconductor element. The current capacity of recent power conversion semiconductor elements is increasing, and in order to secure this large current carrying capacity, a structure in which a large number of semiconductor chips are connected in parallel and stored in one package is adopted. . At this time, it is possible to check whether or not there is an imbalance in the current flowing through each semiconductor chip by detecting the current flowing through all or part of the semiconductor chip in the same package using this Rogowski coil. (For example, refer nonpatent literature 1.).
[0004]
By the way, since it is well known that the junction temperature of the semiconductor element defines the use limit of the element, it is important to measure the current flowing through each semiconductor chip and measure the temperature of each semiconductor chip. Therefore, as in the case of measuring the current, a temperature sensor such as a thermocouple or a resistance temperature detector is attached to all or some of the semiconductor chips in the same package.
[0005]
[Patent Document 1]
JP-A-2001-343401 [0006]
[Non-Patent Document 1]
Masayasu Furuya, Yasushi Ishiyama, “Current Measurement Technology in Flat IGBT Devices”, Fuji Times, Fuji Electric Co., Ltd., August 2002, Vol. 75, No. 8, p453-455
[0007]
[Problems to be solved by the invention]
As described above, the temperature of the semiconductor chip is detected by bringing a thermocouple or a resistance temperature detector into close contact with the element. However, since the thermocouple has a weak output signal, it occurs when the semiconductor element performs a switching operation. Measurement errors may increase due to noise, etc., and a temperature reference point is also required. When using a resistance temperature detector, an extra space is required for the temperature sensor. In either case, since the temperature measurement component must be incorporated into the package, the number of components is increased, and there is a problem that the labor for incorporation is increased.
[0008]
Therefore, an object of the present invention is to realize temperature detection at the same time as detecting the current flowing through the conductor to be measured in an electrically non-contact state without causing an increase in the number of parts and an increase in installation time. Is to make it.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the hybrid sensor of the present invention provides:
An output resistor is connected in parallel to the Rogowski coil via a lead wire to the Rogowski coil arranged closest to the conductor to be measured, and a first current is detected from the voltage of this output resistor. A first temperature detection circuit configured to detect a temperature of the conductor to be measured from the current and the voltage by passing a current through the Rogowski coil; and the output resistor and the first current detection circuit. Instead of a first circuit switch for connecting the first temperature detection circuit to the Rogowski coil.
[0010]
The output resistance is substituted with the input impedance of the first current detection circuit.
The detection position of the voltage input to the first current detection circuit is the output terminal of the Rogowski coil.
A part or all of the Rogowski coil is composed of a conductor selected by giving priority to the magnitude of the specific resistance over the magnitude of the resistance temperature coefficient.
The first circuit switch is provided at the tip of the lead wire.
Instead of the Rogowski coil, a flat pickup coil having one to several turns is disposed immediately around the conductor to be measured, and a second current detection circuit is connected to the pickup coil via a lead wire. A second temperature detection circuit configured to detect a temperature of the conductor to be measured from the current and voltage by supplying a current to the pickup coil; and the second temperature detection circuit instead of the second current detection circuit. And a second circuit switch connected to the pickup coil.
[0011]
The detection position of the voltage input to the second current detection circuit is defined as the output end of the pickup coil.
A part or all of the pickup coil is made of a conductor selected by giving priority to the magnitude of the specific resistance over the magnitude of the resistance temperature coefficient.
The second circuit switch is provided at the tip of the lead wire.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram showing the first embodiment of the present invention. The Rogowski coil 3, the lead wire 4, and the output resistance which are composed of the first conductor 1 and the second conductor 2 shown in FIG. 5 and the first current detection circuit 6 have the same names, uses, and functions as those of the conventional example described above with reference to FIG.
In the first embodiment of FIG. 1, the first circuit switch 11 is installed at the terminal portion of the Rogowski coil 3, and the semiconductor chip 10 as the conductor to be measured (the actual semiconductor chip is a flat plate shape, In order to measure the flow current (shown in a column shape to represent the flow condition), the output resistor 5 and the first current detection circuit 6 are connected to the Rogowski coil 3. The output resistor 5 can be substituted with the input impedance of the first current detection circuit 6.
[0013]
Next, when measuring the temperature of the semiconductor chip 10, the conduction current is turned off and the first circuit switch 11 is switched to connect the Rogowski coil 3 to the first temperature detection circuit 12. At this time, since the temperature of the Rogowski coil 3 and the temperature of the semiconductor chip 10 have risen to substantially the same value, if the conductor constituting the Rogowski coil 3 has a positive resistance temperature coefficient, the resistance value is large. It has become. Therefore, by supplying a current for measurement from the first temperature detection circuit 12 to the Rogowski coil 3, and calculating a resistance value from the current value and the voltage value detected by the current detector 13 and the voltage detector 14, The temperature of the Rogowski coil 3, that is, the temperature of the semiconductor chip 10 can be known. At this time, if the voltage detector 14 is in a position close to the output end of the Rogowski coil 3, the voltage drop of the first circuit switch 11 and the lead wire is not included, so that the accuracy of temperature detection can be improved. it can.
[0014]
FIG. 2 is a block diagram showing a second embodiment of the present invention. In FIG. 2, the Rogowski coil 3 is composed of a conductor having a large specific resistance, and the first circuit switch 11 is read. Although it is different from the first embodiment of FIG. 1 that it is installed at the tip of the wire 4 (position close to the output resistor 5), everything else is the same as FIG.
The lead wire 4 is usually a copper wire, but if a conductor having a large specific resistance, for example, a stainless wire having a specific resistance approximately 40 times that of copper, is used for all or a part of the Rogowski coil 3, the first circuit is switched. When the device 11 is installed at a position far from the Rogowski coil 3, the resistance value of the lead wire 4 is included when measuring the resistance value of the Rogowski coil 3, but the measurement error for that can be ignored. Small enough. Therefore, since the first circuit switch 11 can be installed at a position away from the semiconductor element, it is possible to avoid the concentration of a large number of lead wires 4 and the first circuit switch 11 around the semiconductor element.
[0015]
Note that the material constituting the Rogowski coil 3 preferably has a large specific resistance even if the temperature coefficient of resistance is not large. For example, although the above-mentioned stainless steel wire has a resistance temperature coefficient of only about 25% of copper, the specific resistance is about 40 times that of copper. 10 times. Therefore, the temperature detection accuracy can be increased and the noise resistance is also improved.
FIG. 3 is a block diagram showing a third embodiment of the present invention. FIG. 3 shows the detection of the current flowing through the semiconductor chip 10 using the pickup coil 20 instead of the Rogowski coil 3. In FIG. Although different from the first embodiment described above, other names of the lead wire 4, the second circuit switching device 21, the second temperature detection circuit 22, the current detector 23, the voltage detector 24, and the second current detection circuit 26 Are different, but their functions are almost the same. That is, the pick-up coil 20 and the second current detection circuit 26 detect the current flowing through the semiconductor chip 10, but by switching the second circuit switch 21, the pick-up coil 20 becomes a temperature measuring resistor, and the resistance value changes. The second temperature detection circuit 22 detects the temperature of the pickup coil 20, that is, the temperature of the semiconductor chip 10. As in the case described above, if the voltage detector 24 is positioned close to the output end of the pickup coil 20, the voltage drop of the second circuit switch 21 and the lead wire is not included, so that the temperature detection accuracy is improved. Can be improved.
[0016]
FIG. 4 is a block diagram showing a fourth embodiment of the present invention. Like the second embodiment described with reference to FIG. 2, the pickup coil 20 is made of a conductor having a large specific resistance so that the resistance is increased. Even if the temperature coefficient is not so large, the amount of change in the resistance value corresponding to the temperature change can be increased. Therefore, even if the second circuit switch 21 is installed at a position away from the pickup coil 20, the resistance value of the lead wire 4 is increased. This is not an error factor in temperature measurement, is less susceptible to noise, and can avoid the concentration of the lead wire 4 and the second circuit switch 21 around the semiconductor element.
[0017]
【The invention's effect】
The conventional Rogowski coil was able to detect the current flowing through the conductor to be measured in a non-contact manner. However, the temperature of the conductor to be measured had a separate temperature sensor attached to the conductor to be measured. Space for installing the temperature sensor was required, and lead wires were also increasing. On the other hand, in the present invention, when current is not measured, the circuit is switched and a Rogowski coil or a pickup coil is used as a resistance temperature detector, so that it is not necessary to attach a separate temperature sensor and the installation space is reduced. It is also possible to obtain the effect of eliminating the need for mounting. Furthermore, these Rogowski coils or pickup coils can be made of a conductor having a large specific resistance even if the resistance temperature coefficient is not large, so that the amount of change in the resistance value with respect to the temperature change can be increased. Even if the resistance value is measured with the lead wire included, the error at that time will be negligibly small, so install a circuit switch for temperature measurement at a position away from the conductor to be measured. it can. Therefore, it is possible to obtain an effect of avoiding the problem that the circuit switch and the lead wire are concentrated around the conductor to be measured.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a first embodiment of the present invention. FIG. 2 is a block diagram showing a second embodiment of the present invention. FIG. 3 is a block diagram showing a third embodiment of the present invention. 4 is a block diagram showing a fourth embodiment of the present invention. FIG. 5 is a block diagram showing a general configuration for detecting a current flowing through a conductor to be measured by a Rogowski coil.
DESCRIPTION OF SYMBOLS 3 Rogowski coil 4 Lead wire 5 Output resistance 6 1st electric current detection circuit 10 Semiconductor chip 11 as a to-be-measured conductor 1st circuit switcher 12 1st temperature detection circuit 13 and 23 Current detector 14 and 24 Voltage detector 20 Pickup Coil 21 Second circuit switch 22 Second temperature detection circuit 26 Second current detection circuit

Claims (11)

An output resistor is connected in parallel to the Rogowski coil via a lead wire to the Rogowski coil arranged closest to the conductor to be measured, and a first current is detected from the voltage of this output resistor. In a current sensor equipped with a detection circuit,
A first temperature detecting circuit for detecting a temperature of the conductor to be measured from the current and voltage by passing a current through the Rogowski coil; and the first temperature detecting circuit instead of the output resistor and the first current detecting circuit. A hybrid sensor comprising: a first circuit switching device connected to the Rogowski coil. The hybrid sensor according to claim 1,
The hybrid sensor, wherein the output resistance is substituted with an input impedance of the first current detection circuit. In the hybrid sensor according to claim 1 or 2,
A hybrid sensor, wherein a detection position of a voltage input to the first current detection circuit is an output end of the Rogowski coil. The hybrid sensor according to claim 1, wherein:
A hybrid sensor characterized in that a part or all of the Rogowski coil is formed of a conductor having a large specific resistance. The hybrid sensor according to claim 1, wherein:
A hybrid sensor, wherein a part or all of the Rogowski coil is made of a conductor selected by giving priority to the magnitude of the specific resistance over the magnitude of the resistance temperature coefficient. The hybrid sensor according to any one of claims 1 to 5,
The hybrid sensor, wherein the first circuit switch is provided at a tip of the lead wire. In a current sensor for detecting a current flowing through a conductor to be measured by connecting a second current detection circuit to a flat pickup coil via a lead wire with the number of windings arranged one or several times closest to the conductor to be measured. ,
A second temperature detection circuit for detecting a temperature of the conductor to be measured from the current and voltage by passing a current through the pickup coil; and the second temperature detection circuit is connected to the pickup coil instead of the second current detection circuit. And a second circuit switching device. The hybrid sensor according to claim 7,
A hybrid sensor, wherein a detection position of a voltage input to the second current detection circuit is an output end of the pickup coil. The hybrid sensor according to any one of claims 7 to 8,
A hybrid sensor, wherein a part or all of the pickup coil is made of a conductor having a large specific resistance. The hybrid sensor according to any one of claims 7 to 9,
A hybrid sensor characterized in that a part or all of the pickup coil is made of a conductor selected by giving priority to the magnitude of the specific resistance over the magnitude of the resistance temperature coefficient. The hybrid sensor according to any one of claims 7 to 10,
The second sensor is provided at the tip of the lead wire.

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