Conference Agenda

A new method is proposed for the generalized distributed capacitance matrix extraction of multi-conductor transmission lines (MTLs) composed of insulated cables based on S-parameter measurements in this paper. The theoretical derivation of the proposed method is presented. Then, a simulation model is established, and the distributed capacitance matrix of the model is extracted according to the proposed method. The terminal responses of the MTLs are calculated according to the distributed parameters extracted through the S-parameter measurements and calculated based on the analytical formula. The calculated results are compared with the simulation results. The simulation results demonstrate that the proposed method can accurately extract the distributed capacitance matrix of the MTLs. The results also indicate that significant errors are introduced when the analytical formula under wide separation approximation is used to calculate the distributed capacitance matrix of MTLs composed of insulated cables. In contrast, the proposed method is accurate. The proposed method is believed to have strong potential for applications in electromagnetic radiation analysis and field-line coupling of MTLs composed of insulated cables.

Pre-evaluation by simulation is becoming increasingly important to reduce the costs and time in EMC testing. This paper constructs an equivalent circuit of the transmission line constructed with a two-conductor oblique cable and the conductive plane used in the conducted disturbance test. First, the transmission line was approximated using the staircase model, and the equivalent circuit values were determined for each step. Next, the radiation resistance value was determined from the current distribution and the radiated power and embedded in the equivalent circuit. The capacitance value between the connector input and the conductive plate and between the DUT and the conductive plate were then calculated and embedded in the equivalent circuit. The validity of the equivalent circuit was evaluated by comparing the measured and calculated values using mixed-mode-S-parameters. The characteristics of the differential-mode transmission and reflection above 100 MHz agreed with the measured values. For the common-mode characteristics, the calculated resonant frequencies differed from the measured values.

For battery electric vehicles (BEVs), high voltage cables are commonly used in the electric powertrain system. To mitigate the ageing problem of cable shields and decrease the weight of BEVs, unshielded cable harnesses have become popular in the automotive industry. The use of unshielded cables, however, increases the risk of higher crosstalk levels. For the chassis and car body in a BEV, the sheet metals are often overlapping and may be electrically connected or not. This study combines both experimental and numerical investigations, to show that a simulation tool can be used for sensitivity analysis. Regarding the parameters of interest, the simulation results show that for the glue joints only, the variation of gap distance and overlap distance affects the crosstalk level a lot, whereas for overlapping ground planes with glue and flow-drill screw joints, these two parameters have a small effect, even the screw distance’s impact is not pronounced. Compared to the single ground plane, the cable distance and installation height still plays an import role in crosstalk level.

Radiated emissions of in-vehicle equipment are determined by noise sources such as a switching device, a wire harness, and a connector. This paper discusses radiated emissions contribution of the wire harness among these components. Specifically, the shielding characteristics of shielded wire harnesses were evaluated using the triple coaxial method specified in the IEC 62153-4 series. The characteristics were evaluated not only when common mode was applied but also when differential mode was applied. In comparison, the leakage from the shield is higher when common mode is applied, as is generally known. However, the difference between them is only a few dB, depending on the cable. In addition, the radiated emissions from the wire harness were measured. The measurements were performed by modifying the CISPR 25 measurement system to facilitate comparison with the shield characteristics. When the differences between the two types of shielded cables were evaluated, there was a strong correlation between the shield characteristics and the radiated emissions.

Wire-harnesses are an essential element in electromagnetic noise propagation in vehicles, but because many electric wires run parallel and branch, analyzing their propagation is not simple. To solve this, a method is proposed that formally models the branching harness as if it were a single wire bundle by virtually folding the harness at the branching points and other characteristic discontinuity points, providing better analysis prospects

Furthermore, in order to expand the analysis to include radiated emissions, the electromagnetic field is simulated as an incident field induction problem by inverting the transmission and receiving, and the reciprocity theorem is used to determine the emission characteristics, thereby eliminating the need for repeated radiated emission simulations.

The validity of the proposed method has been confirmed using a simple system composed of two lines and comparing the result with an existing circuit simulator and an electromagnetic simulator.