Jung Ick Moon

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 coils 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%.

Generation of Free Space Radiation Patterns From Non-Anechoic Measurements Using Chebyshev Polynomials

Generally, antenna radiation patterns are measured in an anechoic condition so that the presence of undesired reflections does not skew the final measurements. The objective of this communication is to search for methodologies which can extract meaningful approximate results from non-anechoic measurements. In other words, how to process the reflection contaminated data and extract valuable information when one does not have a good anechoic room and performs measurements with various undesired reflections present in the data. The Chebyshev polynomials are used to extract from the data collected under non-anechoic environment and generate a radiation pattern for the same antenna radiating in free space conditions. The problem with this method is that some a priori information is required about the environment. Measured data has been used to illustrate the applicability of this new methodology and its improved performance over the FFT based methods.

System level power control algorithm in wireless power transmission for reducing EMF

In this paper, the system level power control algorithm in wireless power transmission for reducing EMF is presented. To design the power control algorithm, EM simulation is carried out using HFSS EM simulator. Depending on the simulation results, the power control zone is set. For the system level power control, the communication between the transmitter and the receiver is adopted by FSK at 433MHz. The magnetic resonance method is used for wireless power transmission system to implement the power control algorithm. The system can transmit up to 100W is designed and implemented for a docent robot that consumes 60W in order to verify the effectiveness of the power control algorithm.