Minimizing Converter Requirements of Inductive Power Transfer Systems With Constant Voltage Load and Variable Coupling Conditions

This paper proposes a combined design and
control method for inductive power transfer systems that
eliminates the need for overrating the converters in applications
where the coupling conditions vary significantly during
operation. The method is developed for series–series
compensated systems with only one active power electronic
converter and a diode rectifier connected directly
to a constant voltage dc bus or a battery. The worst-case
voltampere requirements are minimized by shaping the frequency
characteristics of the system. Rated power flow during
coupling variations is achieved by frequency control at
constant voltage. Design guidelines are given to achieve
close to unity power factor, constant current amplitude,
and minimum switching losses for the converter over the
whole coupling range. Due to the simple system configuration
requiring only one active converter with minimum
rating, the method is deemed particularly suited for highpower
applications. The properties of the investigated system
configuration are demonstrated by theoretical analysis
and time-domain simulations. Effectiveness and feasibility
of the proposed method are also validated by experimental
measurements from a small-scale laboratory prototype.