부산대학교 도서관

Electrical power converters use semiconductor switching devices for a larger loss reduction compared with non-switching power linear amplifiers, such as class-B amplifiers. However, it is well known that the switching operation produces harmonics and electromagnetic interference noise; consequently, passive components are usually required for the suppression of these harmful subproducts. The use of recent fast power devices such as silicon carbide and gallium nitride devices produces larger dv / dt and di / dt than Si power devices, and, as a result, the above-mentioned problem becomes more tangible. In this study, we propose the concept of a family of multilevel linear amplifiers (MLLA) in which no switching power conversion is possible. MLLAs consist of series-connected switching devices, and only one of them operates as a linear amplifier, and the loss is much less than that of the class-B amplifier. The concept of the family is very useful when a proper MLLA topology is selected for application. In this study, three types of MLLA—diode-clamped, flying-capacitor, and novel modular-cascaded linear amplifiers—with four devices connected in series were investigated, and an efficiency of >82% was demonstrated in the experiments.