While electric cars are often touted as being less mechanically complex than their internal combustion-engined counterparts, there is at least one way in which they’re considerably more “involved” – their radios. Because electrical signals emitted by the car can potentially interfere with incoming radio signals, manufacturers must do things such as insulating the motor and shielding the cables. This adds time and material expenses to the production process. Now, however, researchers from Germany’s Fraunhofer Institute for Reliability and Microintegration have developed technology to help minimize the problem.
The Fraunhofer team applied calculations based on the operation of the major components of electric vehicles, to create a computerized simulation of the whole electrical system found within a typical electric car. Using this model, engineers can virtually try out different placements of parts, in order to determine what offers the least electromechanical interference.
If interference does occur with a particular layout, the model can identify its point of origin, also indicating how it will spread.
“The size and position of individual components – including the electric motor, the battery, the air-conditioning compressor, the charging system, the DC/DC converter and the frequency converter ... play a crucial role,” said project leader Dr. Eckart Hoene. “How and in what direction cables are installed is just as important, as is the thickness of their insulation. With the help of simulations, we can also advise on the quality of the insulation and the plug connectors.”
The frequency converter poses a particular challenge to decent radio reception. This device converts electrical energy into mechanical energy, controlling both the speed and rotational direction of the motor. To do this, the converter rapidly switches the current on and off – this process creates electromagnetic interference, which in severe cases can actually be heard over the car radio.
Hoene’s team has addressed this problem by designing a new type of symmetrical power module – which is a key part of the frequency converter – that eliminates the interference. That module is currently in the prototype stage.