Auxiliary series resonant converter: a new converter for high-voltage, high-power applications

The power converter presented in this paper has been designed to meet high-quality power requirements in high-voltage, high-power applications such as X-ray imaging, traveling wave tube RF generation, etc. The new power converter is based on a series resonant power converter (SRC) which is modified by adding low power auxiliary circuitry. The so obtained auxiliary SRC (ASRC) maintains zero-voltage switching (ZVS) for both main and auxiliary devices over the entire operating range. The ASRC can operate and regulate voltage even at no load conditions. The additional reactive energy used to maintain soft switching and voltage regulation at light loads is controllable independently of power converter load. This contributes to higher efficiency, especially at heavy loads. The ASRC control is identical to that of a standard SRC, so fast and robust transient response can be obtained with relatively simple controller structure. The paper also presents power converter analysis and design, and experimental results from a 100 kW, 150 kV prototype.