5W wireless power transmission system with coupled magnetic resonance

In this paper, a 1.8MHz and 5W wireless power transmission system for a wireless smart storage using coupled magnetic resonances is presented. The proposed wireless power transmission system consists of the 20W class-F power transmitter, two magnetic resonance couplers and 50W full bridge diode rectifier receiver. The transmitter is composed of DDS(Direct Digital Synthesizer) block, class-F power amplifier and control block to implement the frequency and power setting by embedded MCU. Two magnetic resonance couplers are designed with a small spiral resonator. The diameter size of the transmitting spiral coil is 30cm and the receiving coil's size is 7cm. The receiver is composed of full bridge diode rectifier, overvoltage protection (OVP) with active dummy load, DC to DC converter. The power consumption of the wireless smart storage is about 5W and the total power efficiency of this system is about 45%.