Advancing the Performance of a Switched-Mode Radio Frequency Power Generation Architecture

Abstract

This thesis proposal explores performance improvements of a recently proposed switched-mode power generation architecture - the Multi-Inverter Discrete Backoff (MIDB) system - that is currently in development. The RF power system is intended to be used in applications such as radio frequency plasma generation for semiconductor fabrication. Improvements in efficiency are desired due to the high frequency and power levels seen during this process.

There are two main aspects of the proposed thesis. The first aspect of the thesis is to improve the efficiency of the power combining of the multiple power amplifiers used to construct the MIDB system. The architecture utilizes transmission line transformer-based power combiners. A first step is to create a more accurate combiner model at the required operating frequency which better addresses the loss and performance of this transformer structure, including the interaction of transmission line capacitance and the magnetizing inductance of the core. This characteristic was not previously modeled in the traditional combiner model. After making a more accurate model, a physical capacitor is added to the combiner design to achieve resonance at the operating frequency in order to limit the impedance distortion seen in power combining owing to these parasitics. It is then explored how to best design the combiner to achieve high efficiency at low impedance distortion.

The second aspect of the thesis is to develop an interface for the FPGA-based control circuitry and the MIDB power system. There are two proposed ideas for the implementation of the controller, and a feedforward approach is implemented.