Design and analysis of an Electromagnetic Automotive Suspension System with Finite Element Method for Energy Harvesting

Given the growing interest in electric mobility, and analyzed its problems, we can notice that the most relevant is the one related to autonomy. For this reason, the development of innovative recovery systems, together with batteries, is essential for the advent of electric mobility. Analyzing deeply the method of energy recover we can see that the majority concern with the recovery of the kinetic energy, in particular of two methodologies: Regenerative Braking System and Energy Harvesting Suspension, the first is the best known (in fact in the last years was also commercialized) while the latter is less common, and so, the most interesting to study and develop. By definition, energy recovery is the conversion of energy losses that we can observe in various stages of the processes, taking place in mechanical systems that are powered by an energy source in the way of available energy by means of specially designed devices and re-use if needed. The recovered/harvested energy can be used to start various electrical devices or to recharge the battery. The search for maximum energy recovery leads us to work in conditions of low damping, this leads us to deduce that our damper will have a variable behavior depending on the road on which it is located, in particular, it will be preferred to make it works as a generator only in situations of low damping, i.e. on the motorways; while in the remaining conditions (i.e. high damping factor) it will have to work like classical shock absorber. Regarding the model, the two main parts are stator and slider. In the first one there is a casing in which there are housed coils - in particular, a block of three since we want a three-phase output signal. The stator is the part where the eddy current were generated, for that reason the coils are made of copper (material with very high electrical conductivity); after that the current is conveyed to the energy management systems of the vehicle itself. The second one is the slider, here we can find the permanent magnets alternated by iron poles that are used to concentrate the magnetic flux and block physically the magnets - since they are threaded into the shaft. It is the relative motion of the slider with respect to the stator that generates the currents which we have already talked about. Therefore, my thesis, starts from the analysis of the future mobility, understanding both its current advantages and limitations and trying to solve them. Moreover, it continues with a comparison among the various technologies present to date and ends with the development of an eddy current electromagnetic shock absorber to convert the kinetic energy into electrical ones, energy which would otherwise be dissipated in heat. The whole development was done utilizing the Finite Element Method using COMSOL Multiphysics software.