What is Vehicle-to-Grid (V2G)

This chapter describes two methods whose purpose is to estimate the coupling factor k for the inductive coupling of an experimental prototype designed for the contactless battery charging of electric vehicles. The air gap that separates the two square-shaped coils of the inductive coupling is 150 mm. The first method is analytical and provides an expression with which to calculate the mutual inductance between both coils by solving Neumann's formula, from which k readily follows. The second approach is empirical and combines data from waveforms of currents that were obtained both experimentally and from PSpice simulations, where k is a model parameter, under different loading conditions. The agreement between the analytical and the empirical method is good, as they both yield coupling factor figures that are equal to 0.197 and 0.200, respectively. Both techniques could, therefore, be applied in order to determine the coupling factor of the constructed inductive coupling for other air gaps near to 150 mm, which are also of practical interest in electric vehicle charging.