Analysis and Design of Three-Coil Structure WPT System With Constant Output Current and Voltage for Battery Charging Applications

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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Theoretical Analysis and Design of an Innovative Coil Structure for Transcranial Magnetic Stimulation

Applied Sciences ◽

10.3390/app11041960 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1960

Author(s):

Naming Zhang ◽

Ziang Wang ◽

Jinhua Shi ◽

Shuya Ning ◽

Yukuo Zhang ◽

...

Keyword(s):

Electromagnetic Field ◽

Transcranial Magnetic Stimulation ◽

Theoretical Analysis ◽

Numerical Simulations ◽

Magnetic Stimulation ◽

Influential Factors ◽

Intersection Angle ◽

Electromagnetic Field Distribution ◽

Analysis And Design ◽

Coil Structure

Previous research showed that pulsed functional magnetic stimulation can activate brain tissue with optimum intensity and frequency. Conventional stimulation coils are always set as a figure-8 type or Helmholtz. However, the magnetic fields generated by these coils are uniform around the target, and their magnetic stimulation performance still needs improvement. In this paper, a novel type of stimulation coil is proposed to shrink the irritative zone and strengthen the stimulation intensity. Furthermore, the electromagnetic field distribution is calculated and measured. Based on numerical simulations, the proposed coil is compared to traditional coil types. Moreover, the influential factors, such as the diameter and the intersection angle, are also analyzed. It was demonstrated that the proposed coil has a better performance in comparison with the figure-8 coil. Thus, this work suggests a new way to design stimulation coils for transcranial magnetic stimulation.

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