HEMS Assisted by a Sensor Network Having an Efficient Wireless Power Supply

Home energy management system (HEMS) is expected as one of the promising technologies to satisfy the demand. We are developing HEMS assisted by a sensor network having an efficient wireless power supply in order to be spreading around the people. Then we have studied the resonant-type wireless power transmission applying for HEMS because the transmitting power is comparatively high in the middle range by using resonant way. In our study, we have derived the formula of transmitting power efficiency in the system of including exciting coil and resonant coil. And the transmitting characteristic using single loop coil is measured. The calculated value with derived equation and measured value are in good agreement. Also we have tried to calculate using electromagnetic numerical method. After showing the validation of both calculation methods, we have examined the way of coil arrangement that transmitting distance is more than 1 m under the condition of human body safety protection guideline from electromagnetic wave. Finally we have arrived at the design of using the pair resonant coils which are very large coil for transmitting and the small coil for receiving. Then we have calculated the transmitting characteristic using electromagnetic numerical method and concluded this design is very useful for HEMS.