Modeling, Sensitivity Analysis, and Controller Synthesis of Multipickup Bidirectional Inductive Power Transfer Systems

Inductive power transfer (IPT) systems are increasingly being used in numerous industrial applications, which essentially require power without any physical contacts. In contrast to unidirectional IPT systems, bidirectional IPT systems are inherently higher-order resonant networks and relatively complex in modeling, design, and control. The complexity further exacerbates with the increase in number of pickups or loads, making design and implementation of such systems a real challenge. This paper, therefore, develops a multivariable dynamic model for a multipickup bidirectional IPT system, which can provide an accurate insight into the behavior of this system and can be used for controller synthesis under variations of component values. The output sensitivity to various parameters and the interaction among various control variables and degree of controllability of the system are investigated using frequency domain analysis. The validity of the model is verified under various operating conditions by comparing the predicted behavior with a 1-kW prototype of a bidirectional IPT system with two pickups. Measured results convincingly demonstrate that the proposed model accurately predicts the dynamic behavior of bidirectional IPT systems with multiple pickups and can, therefore, be used as a valuable tool for both dynamic analysis and controller design.