Optimizing the Operation of Charging Self-generating Resonant Inverters

This paper reports a study of the electromagnetic processes in self-generating resonant inverters, as well as the derivation of analytical dependences of their operating frequency on the parameters of the resonance circuit and positive feedback circuits, in order to expand the range of their output power and optimize their operation. The object of research is electromagnetic processes in resonant inverters, in which autogeneration of resonant current oscillations is carried out in the process of operation. The results of studying the electromagnetic processes in sequential self-generating resonant inverters based on the characteristics of the resonant circuit are presented. The operating modes of the inverters have been optimized by setting certain ratios between the operating and resonant frequencies at unstable circuit parameters. The ratio of operating and resonant frequencies is set through the use of phase-shifting filters in a positive feedback loop along the circuit current and correspond to the autogenerator mode. The conditions of self-generation in converters with a sequential resonant circuit have been determined. Mathematical expressions have been built for determining the coefficients of positive feedback on the current and voltage of the resonant circuit, which made it possible to derive target analytical dependences. Analytical dependences of the established operating frequency on the parameters of the circuit and phase-shifting filters have been established. Based on the obtained dependences, the parameters of the positive feedback circuits have been determined in order to ensure a wide range of output power of the converters. The resulting dependences make it possible to carry out theoretical calculations whose results repeat the results of model experiments. Phase characteristics of the resonance circuit and various phase-shifting filters, which can be part of a serial resonant converter, have been constructed. The results of the analysis reported here could be used in the design of resonant inverters with unstable circuit parameters, in particular in inductive chargers