Energy transfer characteristics analysis of MCR-WPT system with intermediate coils

For the wireless power transmission with medium and long transmission distance, the intermediate coil is a good solution. In order to analyze intermediate coil transfer characteristics of the single, double and three layers, firstly, based on the understanding of the circuit structure of the Magnetic coupling resonance wireless power transfer (MCRWPT) system, the theoretical calculation formula of output power and efficiency is deduced according to Kirchhoffs law. Then, mutual inductance of coils and magnetic field strength was simulated in ANSYS Maxwell. On the premise that mutual inductance of the three coils was approximately equal, the number of turns of the three coils was obtained, and the theoretical value of AC resistance was calculated by using the formula. Finally, the experimental platform is built to measure the actual mutual inductance, self-inductance and AC resistance, and calculate their transmission efficiency. The results show that the single layer coil has the smallest internal resistance and the highest transmission efficiency at 200 kHz and 32 cm transmission distance. Finally, the rationality of the theoretical calculation formula of Litz-coil resistance is verified by experiments.