G. Gong, H. Ertl, J.W. Kolar:
"High-frequency isolated DC/DC converter for input voltage conditioning of a linear power amplifier";
Poster: IEEE PESC (Power Electronics Specialists Conference), Acapulco, Mexiko; 06-15-2003 - 06-19-2003; in: "Proceedings of the 34. IEEE Power Electronics Specialists Conference ", Volumen 4 (2003), ISBN: 0-7803-7755-9; 1929 - 1934.

Conventional linear power amplifiers show a high
output voltage quality but are characterized by high power losses
and/or low power density. Therefore, there is a growing interest in
increasing the efficiency of linear power amplifiers, e.g. for the
realization of high power testing voltage sources.
In this paper a high-frequency isolated DC/DC converter sys-tem
is proposed for the conditioning of the input voltage of a linear
power amplifier. The output voltage of the DC/DC converter is
varied according to the output voltage to be formed by the linear
power amplifier so that the voltage drop occurring across the power
amplifier output transistors is reduced to low values which results in
a significant increase of the total system efficiency. The control
design of the DC/DC converter is for fast output voltage response
according to the high large signal bandwidth of the linear power
amplifier. The three-level input stage of the proposed system does
allow a direct connection to the output of a three-phase three-level
PWM rectifier ensuring low effects on the supplying mains.
The operating principle of the proposed system is described and
the design of the output voltage control is treated in detail. The
resulting dynamic behavior of the system is analyzed by digital
simulation. Finally, the theoretical considerations are verified by
measurements on a 1.5kW laboratory prototype.

http://aleph.ub.tuwien.ac.at/F?base=tuw01&func=find-c&ccl_term=AC04403755