The use of dielectric coatings in capacitive power transfer systems

Capacitive power transfer (CPT) is emerging as a competitive alternative to inductive power transfer (IPT) for non-contact applications over short distances. One distinct advantage CPT has is that the electric field is mostly contained between the coupling plates. These plates are in or near contact with each other but are galvanically isolated by an insulating coating. This paper discusses the function dielectric coating have in CPT and gives insight to their design. Ceramic coatings are presented as a viable option given their durability, high permittivity, dielectric strength and ease of application. Specifically, titanium dioxide is identified as a ceramic coating ideally suited for CPT applications. Titanium dioxide is coated on both aluminum and stainless steel substrates via relatively new sol-gel process. This process is documented step by step with the thickness and chemical composition of the coating verified by scanning electron microscope. The effective permittivity and dielectric breakdown strength of the titanium dioxide coatings are measured.