Transformer flux leakage modeling and optimization of contactless power converter with an air gap of 1cm for small power applications

DC - DC converter topology with small size, light weight and high conversion efficiency has an increasing demand on small power applications such as mobile phone chargers, robotic chargers and EV systems. Designing techniques to transmit electrical power using specially constructed ferrite cores are already developed to ensure maximum flux linkage. However, particularly while designing chargers for portable and small appliances large size and large volume cores cannot be used as they are inappropriate for the application. Therefore, designing a system with small size, less weight and cheap cost also greatly expected as equal as efficiency for producing an effective converter and to make it fit for a specific application. At the same time, these kinds of compatible cores suffer severely by eddy current loss at high frequency range due to leakage flux. Due to leakage flux, characteristic of the converter system also varies with respect to frequency. Therefore, an efficient trade-off must be carried out while designing a contactless converter system for various compact commercial applications. In this paper, to analyze the effects of leakage flux and its consequences in contactless power converters, the prototype is subjected to experimental analysis. The frequency dependant model of the transformer is presented to realize the consequences of leakage flux by simulation by which the analysis of the converter is carried out. Finally, using a frequency dependant model, the system was optimized by quantitative analysis.