Wireless power transfer system for docent robot by using magnetic resonant coils

A wireless power transmission system for 1.78MHz, 60W docent robot using coupled magnetic resonances is presented. The proposed wireless power transmission system consists of a 130W class-F power transmitter, two magnetic resonance couplers and 60W full bridge RF rectifier receiver. The transmitter is composed of DDS (Direct Digital Synthesizer) block, class-F power amplifier and VSWR measurement block to implement the frequency searching and power tracking function. Two magnetic resonance couplers are designed with a small spiral resonator. The diameter size of the spiral coil is 30 cm (1.8λ/1000). The receiver is composed of RF rectifier, overvoltage protection (OVP) with active dummy load and DC to DC converter. The charging power of the docent robot is about 48W and the entire DC to DC system efficiency of this WPT system is 54%.