The Design and Fabrication of Multiple-Transmitter Coils and Single-Receiver Coils for a Wireless Power Transfer System to Charge a 3s LiPo Drone's Battery

Recent research has shown an increasing interest in wireless power transfer (WPT) technology for drone batteries. The inconvenience of wired charging, especially for drones, is a huge obstacle. In this research project, a WPT platform was proposed by applying four transmitting coils and a single receiving coil. To meet the industrial standards required for transmitter Tx and receiver Rx, a calculation of the parameters was implemented. An H-bridge MOSFET was used as a DC-AC inverter, a bridge diode was used as an AC-DC rectifier, and a Pi low pass filter was added to the receiver circuit design to filter the high-frequency noise. Experimental investigations were conducted to study the maximum power and power efficiency of the coil's alignment. The focus of this article was to design and fabricate workable multiple-transmitter coils and a single-receiver coil for a wireless power transfer system, in order to charge a 3S LiPo drone's battery. It not only covers an overview of wireless power transfer but also includes the method for charging a 3S LiPo drone's battery, a misalignment study on the X and Y axes of the wireless charging system, and a stable charging of the battery that does not exceed the maximum current of 1.26 A for healthy charging. An efficiency of 58.29% was achieved at a power of 14.924 W and the minimum value was found to be 0.008 W. The efficiency of the typical coil design and the proposed coil design were 55.04% and 12.06%, respectively. The charging current obtained was 1.27 A, which gives an estimated charging time of 3.31 h based on the calculation. The actual charging time of the 3s 4200 mAh 11.1 V LiPo battery was 2 h.