Analysis and comparison of series-series and series-parallel topology of contactless power transfer systems

Due to large leakage inductance, compensation is usually necessary in contactless system to achieve the required power transfer. A contactless power transfer system is designed with two such compensation topologies and are presented in this paper. Primary compensation is designed to make the primary phase angle equal to the secondary resonant frequency with minimum VA rating of the power supply. Secondary compensation is designed to increase the power transfer capability. The theory of contactless system is explained with analytical expressions for voltage, current and impedance as well as the power transfer efficiency. Using 18cm × 14.5cm primary coil and 19cm × 11cm secondary coil, a functional contactless system is realized in the laboratory. The operating characteristics of contactless system at various frequency of operation, loads and distances with the two compensation techniques are detailed. Efficiency of two compensation techniques in various operating conditions are found and compared.