A Bipolar Pad in a 10-kHz 300-W Distributed IPT System for AGV Applications

This paper presents the magnetic analysis of a recently proposed multiple coil pad design, called the bipolar pad (BPP), in a distributed inductive power transfer (IPT) system for automatic guided vehicle (AGV) applications. The paper briefly discusses the magnetic design optimization procedure and then optimizes another recently proposed secondary pad design (generally used in lumped IPT systems), called the double-D quadrature pad (DDQP), for distributed AGV applications and compares its performance with the BPP. A four conductor single phase track topology is used here as primary. Both the pads discussed in this paper have already been shown to perform well in lumped IPT systems and hence the work presented in this paper highlights and validates the possibility of using these pads in mixed distributed/lumped IPT systems. A 3-D finite element modeling tool is used to evaluate and compare all the models presented in this paper. To validate these results, a prototype system is built with a BPP secondary driving a load through a controller circuit. A modification in the traditional control topology is proposed and shown to improve the overall system efficiency; before finally highlighting some of the practical design issues needed to be considered when building such a system.