Design and Analysis of a Detuned Series-Series IPT System with Solenoid Coil Structure for Drone Charging Applications

This paper proposes a new coil configuration that uses solenoid ferrites on the receiver side instead of planar ferrite coils that are employed in existing wireless charging systems. The solenoid ferrites are used in the drone legs to help mount the receiver on a moving truck, while the two parts of the transmitter are placed on the truck. To validate this idea, a detuned transmitter series-series (SS) compensated IPT prototype system has been investigated to charge the onboard battery of a drone. The proposed detuned design helps to limit the system output power and transmitter side current at even zero coupling condition and tolerates misalignment positions. Experimental results demonstrate that the system's switching frequency is 245 kHz, and the primary side resonates at 223.5 kHz, which is a detuned design. The transmitting current is limited to 4.5 A at zero coupling condition with a low power loss of only 4.2 W at zero coupling condition. The target achievable power of the system is 50 W with a 10 mm air gap and horizontal and vertical misalignment in the range of [0, 50 mm]. This system has been validated by experiments to charge an 11.1V battery at 48.2W with 88.2% efficiency.