High-Power High-Efficiency Power Amplifiers for Synchrotron Light Sources

Accelerators used for nuclear-physics research require megawatts of radio-frequency energy. They currently employ vacuum-tube power amplifiers or conventional solid-state amplifiers that are inefficient and therefore consume a great deal of prime power. Many other applications including semiconductor processing, cellular-telephone base station transmitters and military communication systems similarly use inefficient power amplifiers and therefore consume large amounts of electrical power. We will develop two high-efficiency power-amplifier systems that can produce the radio- frequency energy with a much lower consumption of electrical power. This will be accomplished by combining state-of-the art transistors, amplifier techniques, and digital signal processing. Phase I investigated critical areas of technology to determine what could be done and how best to do it. A good deal of Phase I was experimental so that real-world results were obtained and concepts proven. We used these results to develop the best approach to make a high-efficiency, high-reliability power amplifier that can be scaled to the high power levels needed by DOE and other applications. The heart of the scalable high-efficiency power amplifier is a 500-W power module and the associated digital signal processor. Phase II is a step-by-step development of this module including the signal processor, RF final power amplifier, RF drivers, high-level modulators, and control circuits. These components will be integrated into 500-W modules for the Advanced Photon Source frequencies and then multiple modules will be integrated into a 2-kW prototype. Commercial Applications and Other Benefits: The amplifiers developed under this grant can be adapted for use in military communication and jamming, high-field magnetic-resonance imaging, digital-television (HDTV) transmitters, and new applications in the bands vacated by analog television. The proposed amplifiers will significantly reduce the amount of prime power used by DOE accelerators, resulting in reduced operating cost, importation of foreign petroleum, pollution, and green-house gas emissions.