New design method for power transformer in contactless charging of storage batteries for undersea robot

Abstract

Object and purpose of research. The research object is a special power transformer, which is a necessary functional element of the contactless battery charging system for autonomous undersea robots. There are separate primary and secondary parts of the transformer with a non-magnetic gap between windings and center-to-center shift. It is to be taken into account during its design and requires a special purpose method, which is the focus of this study. The suggested method makes it possible to achieve the design parameters for the transformer using a ferrite cup-shaped magnetic conductor optimized for specific power, taking into account onboard undersea robot specifics. Subject matter and methods. The method suggests a system of relative units with a basic value of the outside core diameter. The method is based on the coefficient of magnetic coupling between windings and relative turn inductance completely defining the transformer electromagnetic properties as a function of relative gap and center-to-center shift between windings [1]. Calculations are done using mathematical modeling in Ansys Maxwell and Solidworks software packages. Design parameters of the transformer to provide maximum charge power are determined by maximum ampere turns related to admissible overheating of magnetic conductor with a full use of magnetic conductor aperture. Main results. The number of ampere turns and cross-section of windings are calculated, as well as the invertor frequency is determined at a given supply voltage and range of ferrite cup-shaped magnetic conductors. The calculated transformer parameters have to ensure the maximum wattage at admissible overheating of windings and given nonmagnetic gaps and center-to-center shifts. A case study and full-scale experiment has confirmed the choice of solutions and drawn conclusions. Conclusion. The use of the transformer designed by this method in the system raises the total efficiency of autonomous undersea robots.

Keywords

• contactless charging system
• undersea robot
• high-frequency converter
• non-magnetic gap
• ampere turns
• admissible overheating
• design parameters