Analysis of a cascade double /spl Gamma/-CL current source resonant inverter

The current source resonant inverter (CSRI) is the heart of many systems and equipment, e.g. uninterruptible power supplies (UPS) and high-frequency annealing (HFA) equipment. Many topologies shown in open literature are the series resonant converters (SRC) and parallel resonant converters (PRC) that consist of two or three energy storage elements. However, they have a number of limitations. These limitations of two- or/and three-element resonant topologies can be overcome by adding a fourth energy storage element. This paper introduces a cascade double /spl Gamma/-CL CSRI, which has very smooth waveforms of output voltage and current, and very low total harmonic distortion (THD) value. It effectively reduces the power losses and largely increases the power transfer efficiency. Simulation and testing results verified the design and analysis.