P5.2 - Evaluation of the Mutual Inductance of any Conductor Arrangements for Determining the Position

SENSOR+TEST Conferences 2011
2011-06-07 - 2011-06-09
Proceedings SENSOR 2011
P5 - Magnetic
F. Wießner, C. Rückerl, K. Eichhorn - Forschungs- und Transferzentrum Leipzig (Germany), D. Plohmann - Sensorik-Bayern GmbH, Regensburg (Germany)
768 - 773


Inductive sensors of different works are already used in some areas of measurement and automation application. An inductive position sensor, for example, could be constructed by a moving transmitter coil and one or more fixed-receiver coils. The transmitting coil is supplied with an electric current. This can be analysed at the measured receiver coil signal. For the development of such position sensors, it is necessary to model the mutal inductance between two coils and to determine by calculation. For such tasks often numerical methods and simulation tools are used. For complex coils and wire structures, these numerical methods lead to very complex calculations. These calculations can only be simplified by using any existing symmetry of the arrangement. This paper presents a method to calculated a position and location sensor by using the mutal inductance between the transmitter and the receiver coil of any complex coil geometries. Using the mathematical model of mutual inductance can be deduced from the known inductance of the receiver coil and the metrological mutual inductance on the location and position of the transmitting coil. A simple displacement sensor was calculated, for examble. This sensor system contains four triangle and one square receiver coils and one square transmitting coil. A pair of the triangular receiver coils is used. They point to the opposite direction. The differential voltage of a pair is used for measurement. The differential voltage is linear for small displacements. The square reciver coil is used to measure the distance of the transmiting coil.
Using the calculated results, it is possiple to find an inverse function, which provides a function of the mutal inductance to determine the displacement of the trasmitting coil.
Using this method, one can determine the zero point and linearity of an inductiv sensor. While develop ment phase it can be used for optimize the linearty of inductiv sensors. It is also usable to estimate the measurement range.
This methode is much faster than conventional numerical calculation methods. This is major advantage.