Transient analytical model of eddy current coupler under electromagnetic-thermal coupling

Eddy current coupler is a non-contact power transmission device. But during the operation of eddy current coupler, eddy current losses are continuously generated in the conductor, leading to temperature rise of components and affecting its performance. A transient analysis model under electromagnetic-thermal coupling is established to predict temperature rise and transmission performance. First, for the electromagnetic analysis the three dimensions vector magnetic potential method is used to calculate the eddy current loss power of the conductor and the relationship between the eddy current loss power and the time is obtained. Subsequently, the structure of eddy current coupler is equivalent to a series of concentric rings to form a T-equivalent thermal circuit. Taking the eddy current loss of the conductor as the heat source, an equivalent thermal network model is established to compute the nodal temperature rise of each component. Obviously, the nodal temperature rise is transient. Finally, temperature rise is then fed back to adjust the conductor's electrical conductivity and PMs' remanent magnetism, with iterative calculations repeated until convergence. The transient thermal model which is relative to time enables real-time prediction and updates parameters via temperature feedback. The transient matrix formula is used to solve the variation laws of nodal temperature rise and transmission torque with time, followed by experimental verification. The model results are in good agreement with the experimental results. This transient analysis model provides effective theoretical support for the thermal analysis of eddy current coupler.