Abstract:
With the advent of Inductively Power Transfer (IPT) technology, power transfer has been achieved between movable objects without any electric contacts. This is widely used in the applications where wire connections are inconvenient or impossible to be built between the two objects for power transfer. A conventional IPT system consists of a primary power converter and one or multiple secondary pickup circuits where the primary and secondary coils are loosely coupled with each other. The traditional and most commonly used IPT pickup circuits are tuned with combinations of inductors and capacitors forming a resonant tank for power compensation. However, tuning a circuit can be tedious, particularly when the quality factor Q is high. This research is about the development of a new pickup circuit based on Voltage Sourced Converter (VSC) technology. VSC based pickup circuit can eliminate the need for circuit tuning and greatly reduce the circuit complexity. It can achieve the output power regulation by controlling the VSC as a rectifier instead of using separate additional shorting or dynamic tuning/detuning control. The aim of this research project is to design a power pickup circuit coupled with a primary converter with VSC control for maintaining a constant output voltage at the load side. The thesis contains an introduction to IPT and VSC technology and a system overview. Primary power converter circuit is studied from a theoretical level and implemented in practice. The VSC based pickup circuit has been analysed theoretically and then verified with software simulations. The coding algorithm of the controller used to control the VSC circuit has also been described. The practical system performance has shown that the VSC based pickup up circuit has the capability to rectify and boost up the voltage induced in the pickup coil for a wide range of loads via PWM gate signal duty cycle control strategy. It could be an alternative to the conventional tuning circuit based IPT pickup circuit. Suggestions for the future work to improve the circuit performance are given in the end of the thesis.