Shape design optimization of shielding electrodes for reducing radio interference of HV devices

Developments in computational methods for solving boundary value problems, coupled with the advances in computer hardware, has led to the commercial availability of very efficient computer aided engineering (CAE) tools. The aim of this work is to define a suitable criterion for the shape design optimization of HV shielding electrodes for reducing the radio interference. The experimental part of the investigation consists of standard radio interference voltage (RIV) measurements on test geometries with different sized toroidal and spherical electrodes. A detailed 3D modelling of the test geometries has been carried out using a BEM based commercial code, in order to precisely compute the electric field distribution near the electrode surfaces. It has been observed that, despite the different geometries and applied voltages, a unique electric field value is attained in all configurations in correspondence to the RIV threshold voltage. Therefore, this value can be used as a design parameter for CAE tools once the field distribution near the HV device is computed. The proposed approach may greatly improve the efficiency of HV shield design, which nowadays is normally based on empirical considerations.