Welding power supplies using the partial series resonant converter

The research object is the electromagnetic processes in the semiconductor power converters based on the schemes with circuit commutation and containing resonant circuits of reactive elements and transformers with a small coupling coefficient. The research aim is to develop a technology for a fast wireless battery charging for the use in clean energy vehicles, which would be based on a resonant converter with a pulse-count adjustment with a phase shift control. The latter provides a high energy performance in a wide range of regulation and a low sensitivity to changes in the magnetic system parameters. This is a final report. The report presents the results of the work performed in accordance with the Terms of Reference for the second stage of the scientific and research work. The following theoretical problems have been solved: development of a mathematical model of a series resonant converter with a pulse-count adjustment for contactless inductive energy transmission, which provided a high accuracy for the studies of the electromagnetic processes in the power section of multi-circuit resonant converters for contactless energy transmission, as well as an opportunity to assess the energy parameters of multi-circuit converters at pulse-count adjustment; compilation of mathematical dependencies of the average input and output current values on the number of half-cycles of resonant oscillations during energy transmission to the circuit and energy dissipation, the supply voltage and the resonant circuit’s parameters, which allowed assessing the converter’s energy parameters over a wide control range; compilation of the dependencies of the converter’s output power and coefficient of efficiency on the number of halfcycles of resonant oscillations during energy transmission to the circuit and energy dissipation, on supply voltage and on the resonant circuit’s parameters, which made it possible to evaluate the efficiency of the pulse-count adjustment of resonant converters for contactless energy transmission; realization of a dynamic model of a resonant converter for contactless energy transmission in the form of transfer functions for small disturbances caused by fluctuations in supply voltage, which made it possible to estimate the effect of its instability on the quality of output current stabilization.

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High Power Density, High-Voltage Parallel Resonant Converter Using Parasitic Capacitance on the Secondary Side of a Transformer

Electronics ◽

10.3390/electronics10141736 ◽

2021 ◽

Vol 10 (14) ◽

pp. 1736

Author(s):

Jaean Kwon ◽

Rae-Young Kim

Keyword(s):

Power Density ◽

High Voltage ◽

Electrostatic Precipitator ◽

Power Supplies ◽

Equivalent Model ◽

Resonant Converter ◽

High Voltage Power Supply ◽

Resonant Capacitor ◽

Parasitic Components ◽

Secondary Side

High-voltage DC power supplies are used in several applications, including X-ray, plasma, electrostatic precipitator, and capacitor charging. However, such a high-voltage power supply has problems, such as a decrease in reliability, owing to an increase in output ripple voltage, and a decrease in power density, owing to an increase in volume. Therefore, this study proposes a method for improving the power density of a parallel resonant converter using the parasitic capacitor of the secondary side of the transformer. Due to the fact that high-voltage power supplies have many turns on the secondary side, a significant number of parasitic capacitors are generated. In addition, in the case of a parallel resonant converter, because the transformer and the primary resonant capacitor are connected in parallel, the parasitic capacitor component generated on the secondary side of the transformer can be equalized and used. A parallel cap-less resonant converter structure developed using the parasitic components of such transformers is proposed. Primary side and secondary side equivalent model analyses are conducted in order to derive new equations and gain waveforms. Finally, the validity of the proposed structure is verified experimentally.

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