Design and applications of dynamic inductive power transfer systems: mobile windings and deformable windings

Abstract

Inductive power transfer (IPT) is the technology that transfers electric power by inductively coupled windings. The term dynamic encompasses two key aspects: mobile windings and deformable windings. As static IPT has been applied successfully in various commercial applications for over a decade, more attention is now put on dynamic IPT to get more flexibility that static IPT does not have. Solving the inductances and electromagnetic fields of the windings is a key part of IPT system design. However, existing software tools generally lack the capability to analyse windings under dynamic operating conditions. FEM tools typically consume a large amount of memory and computational time. The other tool, FastHenry, is mainly designed for rectangular cross-section windings and not suitable for Litz wires. To address this issue, a discrete model for air-core Litz wire winding systems is built. The model divides the windings into discrete points and use numerical integral to solve the winding systems. The model is implemented by C++. The C++ implementation accepts text input files containing winding information and generates text output files containing solving results. The C++ implementation is also able to visualize the solving results by plotting them in the 3-D space. The calculation results of the C++ implementation are also validated by comparing several example winding systems to trusted formulae. To demonstrate the benefits of dynamic IPT, some proposed applications are studied. The example application of mobile windings is an air-core ironless linear motor with power provisioning capability to the payloads. It is a combination of dynamic IPT systems and linear motors. This kind of combination can address the issues caused by the cables connecting the movers of high-accurate machines, such as SMT machines and lithography machines. To demonstrate the feasibility of this concept, a prototype motor is constructed, and its performance is thoroughly tested. A further contribution of this thesis is to extend the concept of dynamic IPT systems to involve deformable windings. The examples are two variable linkage structures, referred to as the planar linkage structure and 3-D linkage structure. They are able to change the inductances of the windings installed on them by changing their shapes. The adjustment can be made either manually or automatically to maintain the optimal operating point, typically the point of highest efficiency. Prototypes of the linkage structures are built to test the feasibility. The changes of self-inductances and mutual inductances of the windings are measured in real time. Their ability of improving the efficiency of IPT systems is also studied.

Date of Award	30 Jun 2025
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Long Zhang (Main Supervisor) & Gus Cheng Zhang (Co Supervisor)