Abstract
High-frequency isolation transformers are used to suppress high-frequency patient leakage currents generated in medical equipment. This study analyzed the coil-to-coil capacitance and power transmission efficiency when varying the number (1 or 3) and size (φ25.3 mm or φ34.0 mm) of ferrite cores used in the high-frequency isolation transformer. Analysis results showed that using three φ25.3 mm cores (S3) yielded coil-to-coil capacitance C of 2.84 pF and power transmission efficiency η of 97.85 %. Furthermore, when using three φ34.0 mm cores (L3), C was 4.18 pF and η was 97.21 %, indicating that increasing the number of ferrite cores reduced C. When this high-frequency isolation transformer was inserted into the transcutaneous energy transmission system, for S3, the high-frequency patient leakage current Ip was 6.50 mA and the power transmission efficiency η' was 72.35 %. For L3, Ip was 6.61 mA and η' was 72.92 %, both falling below the regulation value of 10 mA.
