Design of high frequency controlled rectifier for a contactless battery charging system

In this thesis, battery charge current control is aimed in an inductive power transfer system designed for electrical vehicles. Semi-bridgeless active rectifier circuit topology has been used as control circuit on the secondary side. The circuit controls the impedance seen at terminals of secondary side coil controlling the fundamental values of secondary side voltage and current by proper firing signals. In the study, primary side, secondary side and dual side control types have been investigated and control methods in literature for these types have been mentioned. Operating modes of the active rectifier have been explained and e ect of the proposed switching strategy on load have been analysed comparing it with phase shift control. Steady state analysis of the studied system has been made. System performance and optimum load impedance condition have been analysed. Moreover, for both varying frequency and varying load conditions, e ciency, voltage-current gains and input-output power analyses have been made. Also, apparent load under constant input-output voltages and conduction angle have been analysed. In addition, a general coil e ciency comparison among primary, secondary and dual side control methods have been given under di erent input and output voltages. By that way, advantages and disadvantages of proposed method have been compared with other control types. Furthermore, losses of switches have been modelled using piecewise linear model and switching and conduction losses have been formulated. Also, calculations have been compared with experimental results. Design steps, control logic and implementation of system have been given in detail. Experimental measurement results of coupling coe cient, timing diagram of the control logic, secondary voltage-current waveforms for resistive and battery load and step responses of closed loop control have been given experimentally. Finally, e ciency comparison of analysis, simulation and experimental results have been given.