User Interface Based Shield Effectiveness Analysis Modeling Tool for Hybrid Electric Vehicle Three Phase Power Harness 2010-01-0035

In automotive industry, to deal with EMI problems, an efficient and proper screening attenuation measurement method is needed to make high performance and low cost shielded electrical wiring harness. Previously a screening attenuation measurement method titled PHSA (Power Harness screening attenuation) method [ 1 ] was proposed to measure screening attenuation in shielded power cable, which evaluates the shielding performance that prevents radiation from inner core to outside environment. The method was used to practically check the effects on performance of cable shield (shield effectiveness) due to different combinations of length and braid density against radiated noise. But the measurement time for actually performing experimental tests limits measurable combinations to evaluate the shielding performance of the wiring harness.

So, in order to reduce HEV wiring harness shielding effectiveness measurement evaluation time, in this paper we present a concise software modeling to evaluate the shield effectiveness of HEV wiring harness with the ability to analyze the effects of variation in not only cable length and braid density, but also thickness, shield type and load variation of the cable. The methodology used to develop this software modeling involves theoretical analysis on each factor separately and then performing experiments in order to verify the theoretical results obtained. Further more verified theoretical model was implemented as a user friendly graphical user interface to help evaluate initially the performance of the shielding of wiring harness by using desired wiring parameters for HEV (3-phase) power harness. Software model is based on the experimental results obtained by applying PHSA method on each of the factors affecting the shielding effectiveness. We used this software model of shield effectiveness of three phase power cable, to simulate individual and combined effects of selected combinations of cable length, braided density, thickness, and shield type which involves graph extrapolation techniques.

Instead of doing actual experiments to observe each parameter effect separately, this proposed software modeling can be used to simulate results for the desired parameters of power harness collectively. Further analysis to evaluate the effects of non-cable parameters like effect of presence of connectors and termination loads on the shielding effectiveness measured results. It provide easy and quick guideline as a software model regarding selection of optimum wiring harness parameters thus reducing analysis time on cable performance and shielding effectiveness evaluation.