  The series-series compensation topology is widely adopted in many wireless
power transfer applications. For such systems, their wireless power receiver
part typically involves a DC-DC converter with front-stage full-bridge diode
rectifier, to process the high-frequency transmitted AC power into a DC output
voltage for the load. It is recently reported that the current source nature of
the series-series compensation will introduce right-half-plane (RHP) zeros into
the small-signal transfer functions of the DC-DC converter of the wireless
power receiver, which will severely affect the stability and dynamic response
of the system. To resolve this issue, in this paper, it is proposed to adopt a
different rectifier configuration for the system such that the input current to
the DC-DC converter becomes controllable to eliminate the presence of RHP zeros
of the small-signal transfer functions of the system. This rectifier can be
applied to different wireless power receivers using the buck, buck-boost, or
boost converters. As compared with the original wireless power receivers, the
modified ones feature minimum-phase characteristics and hence ease the design
of compensator. Theoretical and experimental results are provided. The
comparative experimental results verify the elimination of the RHP zero,
improved dynamic responses of reference tracking and against load disturbances,
and a larger stability margin.
