Frédéric Lafon

An Original Approach Based on Data Exchange Between Car Manufacturers and Suppliers to Estimate Susceptibility Threshold by Numerical Simulation at Early Design Stage

This study is a result of a close partnership between a car manufacturer and an automotive component supplier. The aim is to develop electromagnetic compatibility models, i.e., immunity models to predict real-world system failure conditions that can occur inside a vehicle. For the study, we selected an interface that manages air-conditioning inside a vehicle recently put on the market. The system model is submitted by an equipment supplier as a compilation of input impedances and threshold transmitted powers causing a malfunction. The predefined model is then used by a car manufacturer on vehicle-level electromagnetic compatibility simulation, by taking into account the harness configuration and the system placement inside the vehicle cab and chassis. In this paper, we detail the complete method and demonstrate its validity.

Modeling IC Snapback Characteristics Under Electrostatic Discharge Stress

This paper presents a novel technique for modeling the electrostatic discharge snapback phenomenon in integrated circuits (ICs). The macromodel is built using standard components: BSIM3v3.2 model for the MOSFET, a bipolar transistor modeled by Mextram 504.7, and a substrate resistor. The IC under test is characterized by its die and package impedance. The model should allow easier simulation program with IC emphasis implementation, high simulation speed, less convergence issues, and wider availability of a gate-grounded n-type MOSFET protection device. Our model determines the interaction between the protection device and the internal circuitry of the IC. The model parameters are extracted with MATLAB script. Simulation results are compared with transmission-line pulsing measurement for a voltage regulator NCV4949 and a controller area network transceiver TLE6250G.

A New Methodology to Predict the Magnetic Shielding Effectiveness of Enclosures at Low Frequency in the Near Field

In this paper, a methodology to calculate the shielding effectiveness of enclosures with slots at low frequency in the near magnetic field is presented. This modeling technique is based on the magnetic moments and the transmission line approach and makes specific assumptions. It is applied to a slot of small size relative to the dimensions of the enclosure. The slot is electrically short. This technique is validated in the case of a real enclosure with numerical simulations and experimental data. This method is dedicated to the case of mechatronics boxes using in electric and hybrid vehicles, it allows obtaining the results with sufficient accuracy precision for dimensioning a magnetic shielding in a short time.

Magnetic Shielding Effectiveness of Enclosures in Near Field at Low Frequency for Automotive Applications

In this paper, a modeling methodology is presented in order to calculate the magnetic shielding effectiveness at low frequency in the near field of enclosures with a slot. The so-called hybrid approach combining analytical and numerical methods is developed and validated experimentally. The application concerns an enclosure with a slot for electric and hybrid vehicles. The developed technique allows finding the order of magnitude of radiated fields for electromagnetic compatibility design in a very short time.

Modeling Methodology of Automotive Electronic Equipment Assessed on a Realistic Subsystem

Conducted disturbances induced into automotive electronic equipment can be predicted in the early design phase by numerical simulation. This supposes a realistic modeling of the cable harness, as well as the electronic equipment. This paper evaluates a modeling method by the results obtained on a realistic automotive subsystem. The latter is composed of two pieces of electronic equipment connected to each other by a cable harness. This test case was performed on printed circuit boards (PCBs) with full or partial ground planes and using a representative sample of harnesses. Simulation results are compared with measurement results using multiple cable harness samples. A good agreement between measurement and simulation can be obtained for PCBs with full ground plane, provided that fringing effects of the electronic components are taken into account in the equipment model.

Inter-laboratory comparison between CISPR25 chambers, identification of influent parameters and analysis by 3D simulation

In automotive industry, the reference standard used to perform radiated emissions measurements is the CISPR25 [1]. Previous works [2-5] already pointed out that between different labs supposed to be CISPR25 compliant, test results obtained on simple equipment could differ quite significantly (more than 10 dB reported). We identified in [2,3] some parameters at the origin of these deviations, linked to the degrees of freedom in the chamber setup definition in CISPR25. A simultaneous analysis based on the inter-laboratory measurements results linked to the chambers definitions and analysis performed with 3D simulation allowed to establish what are the main influent parameters and their significance. This paper exposes the measurements results and analysis over 13 labs as well as the correlation with 3D simulation to justify about the influence of these parameters individually considered.

Radiated emissions modelling from near-field data - toward international standards

As electromagnetic compatibility (EMC) gains ground in todays world of electronics, integrated circuit (IC) and printed circuit board (PCB) modelling methods are of paramount importance during development of EMC compliant products. One such aspect focuses on modelling the emissions from ICs and PCBs, both conducted and radiated forms. This work proposes a method for modelling the radiated emissions of ICs (PCBs, ...) from near-field data. It also describes a universal exchange format for representing and sharing the model data between industrials, academics and EDA simulation tools.

Predicting the installed performance of a RF receiver's antenna in its operational environment

This paper presents a modelling technique that predicts the detuning of a RF (Radio Frequency) receiver ahead of its installation into a vehicle. In fact, since the vehicle is rarely available during the equipments development phase, it becomes necessary to finalise the product even before it can be tested in its operational environment. The proposed model is based on a circuit approach which permits a fast evaluation of the resonant frequency shifting. The comparison with a 3D full wave simulation confirms the robustness of the proposed technique.

Modeling of the shielding effectiveness of enclosures in near field at low frequencies

In this paper, we present a modeling methodology for the prediction of the magnetic shielding effectiveness in the near field at low frequencies. This study shows an analytical method which is based on magnetic moments approximations to predict the shield effectiveness for infinite plane with narrow slot. The results obtained with the proposed method are compared with the numerical results.

Modelling Approaches Taking into Account the Vehicle's Environment in the Development of Embedded RF Receivers

Large and complex systems such as vehicles contain different structures and require various modelling methods and calculation due to the difference between components scales. One of the main issues in the automotive EMC (Electromagnetic Compatibility) is that the car is rarely available during the products development phase, which means that more often, the product must be finalised before even it can be tested in its real environment. This article presents modelling techniques aiming at predicting the real performance of a RF (Radio Frequency) receiver ahead of its installation into a vehicle.