Control of magnetic bearings in wind turbines

Direct drive generators applied to large wind turbines present some problems, such as very heavy and expensive price. The use of magnetic bearings has a possibility to reduce the weight of the direct drive generator. The control system for such magnetic bearings is considered. In the beginning, the thesis discusses the problems of direct drive...

Wideband Hybrid-Class Power Amplifier for Base Station Applications Using LDMOS with Envelope Tracking System

Conventional RF power amplifiers are normally designed for peak efficiency at maximum output power. However, for WCDMA application, the power amplifier often operates at 6-8 dB power back-off. Consequently, when the power is backed-off from its peak point, the efficiency of conventional power amplifier drops sharply. The envelope elimination and...