A dynamic model for bi-directional Inductive Power Transfer systems

Bi-directional Inductive Power Transfer (IPT) systems facilitate contactless power transfer between two sides and across an air-gap, through weak magnetic coupling. These systems constitute a 6th order resonant circuit and, as such, are difficult to design and control. A mathematical model which provides an insight into the behaviour of bi-directional IPT systems would therefore be invaluable at design stage. This paper presents a dynamic model through which the behaviour of bi-directional IPT systems can be accurately predicted. A 1.5 kW bi-directional IPT system is simulated in PLECS, and results are presented with comparisons to demonstrate the validity of the dynamic model. Results indicate that the proposed model accurately predicts the dynamics of the bi-directional IPT system and can therefore be used as a valuable tool for both transient analysis and controller design.