A modified class G amplifier for active magnetic bearings

Author

Maddaleno, Franco ; Carabelli, Stefano ; Muzzarelli, Marco

Author_Institution

Dept. of Electron., Politecnico di Torino, Italy

Volume

1

fYear

1997

fDate

23-27 Feb 1997

Firstpage

534

Abstract

To improve the overall efficiency of a transconductance amplifier loaded by the high inductance and low resistance typical of the magnetic bearing coils, a modified class G amplifier has been developed. A third transistor has been connected from ground to output, in order to obtain high efficiency coil discharge. A simple theoretical characterization has been used to provide some diagrams to optimize the power efficiency as a function of a nonconstant load such as that due to a rotor unbalance. Experimentalal results are reported showing a good agreement with the developed theory

Keywords

load (electric); machine bearings; magnetic devices; power amplifiers; power semiconductor switches; power transistors; active magnetic bearings; coil discharge; inductive load; magnetic bearing coils; modified class G amplifier; nonconstant load; power efficiency optimisation; rotor unbalance; theoretical characterization; transconductance amplifier; Actuators; Coils; Force control; Frequency; High power amplifiers; Inductance; Magnetic levitation; Power amplifiers; Transconductance; Voltage;

fLanguage

English

Publisher

ieee

Conference_Titel

Applied Power Electronics Conference and Exposition, 1997. APEC '97 Conference Proceedings 1997., Twelfth Annual

Conference_Location

Atlanta, GA

Print_ISBN

0-7803-3704-2

Type

conf

DOI

10.1109/APEC.1997.581510

Filename

581510