OPTIMISATION OF THE SHAPE OF THE FERROMAGNETIC CORE OF FLUXSET TYPE MAGNETIC FIELD SENSORS

Abstract

A method is presented for the optimisation of the shape of the ferromagnetic core of fluxset type magnetic filed sensors. The objective of the optimisation is to find a core shape that guarantees the most homogeneous magnetisation of the core due to a given external magnetic field. By finding the optimal shape of the core the sensitivity of the sensor is improved. Since the thickness of the ferromagnetic conducting ribbon core used for fluxset sensors is considerably smaller than its other dimensions, the presence of the core is modelled by magnetic and conducting surface currents flowing in a mathematical surface representing the core. The electromagnetic field is calculated by solving an integral equation derived from the assumption of impedance type boundary conditions on the two sides of this surface. The core shape is optimised by minimising the magnetisation differences at different locations of the core. Simulated annealing procedure is used for the optimisation. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 32-37]