Consideration of interference between parallel connected class D amplifiers operated at different switching frequencies

摘要

Multi frequency coupling is widely used in plasma processing technology in order to improve controllability of plasma chamber. This paper researches about influence of multi-frequency operation of parallel connected high efficiency switching power amplifier, class D amplifiers. In the analysis, it is seen that variation in dc supply voltage of one amplifier leg does not influence to output waveform of another amplifier leg. However, parallel connection of two amplifiers influences output power of both amplifiers due to change in impedance of output filter. A decoupling filter is proposed to the output of higher frequency amplifier to reduce the coupling. It is shown that decoupling filter successfully improved coupling between amplifiers.