EMC test aims for safer cars

Selective Validation is being used to predict electromagnetic interference in the automotive industry


A method for determining the validity of electromagnetic compatibility (EMC) models is helping make electrically equipped cars safer in the future.

The technique, known as Feature Selective Validation (FSV), was developed by researchers at De Montfort University.

Engineers from around the world are now beginning to use the method to ensure the validity of their EMC models, which are designed to predict how a source of interference could affect electronic circuitry.

UK automotive testing specialist MIRA is using FSV in its research on electromagnetic interference in cars and its effect on, among other things, electrical braking systems.

FSV involves a set of equations that can be implemented in any EMC modelling software. The technique separates the raw data plugged into an EMC model into two files and compares and interpolates them. After an intense amount of number crunching, the process will deliver results that tell engineers whether their model is valid and contains enough information.

One of the developers of FSV, Alistair Duffy, a reader in electromagnetics at De Montfort University, said engineers would usually determine whether an EMC model was valid by comparing it with their past experience, which he said is a highly subjective process.

‘FSV provides them with an objective yardstick to use,’ he said. ‘I wouldn’t say it will help revolutionise what they do, but I would like to think it makes what they do more objective and traceable.’

Duffy said he would be willing to work with any engineer interested in using the technique and modelling-software companies are free to build the equations into the code of their programs.

He added that the method has garnered the attention of the IEEE. The international technology organisation has made FSV a part of its standard of ‘Validation of computational electromagnetics for computer modelling and simulation’.

Duffy said determining the effects of electromagnetic fields is a challenging yet extremely important job for circuit designers.

‘Radio waves and electromagnetic energy can interfere with your electronic systems to the point where you have no noticeable effect or it could be fatal,’ he said. ‘For example, that’s why they’re very nervous about having mobile phones near hospital equipment such as the foetal heart monitor.’

Duffy referenced an ongoing research programme at MIRA that is looking into electromagnetic fields in cars. The programme was created in response to the increase in electrical equipment and transmitters in cars and concerns about the interoperability between devices and vehicle systems.

The group is researching whether vital electrical vehicle systems, such as braking, could be hindered or threatened by electromagnetic interference from electrical equipment such as a driver’s mobile phone or laptop computer.

The programme will also address concerns of the possible effects of electromagnetic fields on human health.

Duffy said FSV will be used in their modelling process as they determine optimal frequencies, powers and antenna installations in cars.

Siobhan Wagner