Abstract:

In the traditional system of ICPT, to calculate the optimal ratio of the receiving coils(Rx) of loosely coupled transformer coil and the distance between the transmitting coil (Tx) and the receiving coil (Rx), That is, radius-center distance ratio γ, usually by system modeling to project the mutual inductance value between the Tx and the Rx and supplemented by a large number of experiments. It not only lack theoretical basis but also waste manpower and material resources in this way. Pointing to this problem, this paper proposes a design method, using by simulating and observing the change rules of current density, to obtain the optimal radius-center distance ratio γ. Firstly, the system decoupling equivalent circuit model, that primary and secondary coils are in parallel compensation (PP) structure of the single switch inverter ICPT system, is used to derive the relationship among the current density, mutual inductance (M), system transmission power. Through the formula analysis, the ratio of the Rx inductance (L₁) to the Tx inductance (L₂) and the value of the coupling coefficient λ of the system are determined, and to determine the values of L₁ and L₂ at different frequencies. The simulation model is established in this way and using the finite element simulation software to study the optimal value of γ. Compared with the method of optimizing the coil through the coil mutual inductance value, the current density in this paper can be directly observed by software, vivid, save time and cost, and improve the design efficiency effectively. The simulation results show that the optimal radius-center distance ratio (γ) of loosely coupled coils is consistent with the empirical values summed up by the enterprise experiments.

Key words: Single switch inverter, inductive coupled power transfer, radius-center distance ratio, current density, finite element simulation