Study on Intelligent Battery Charging Using Inductive Transmission of Power and Information

In previous literatures, the authors introduced the technology of the wireless transmission of power and information (WTPI). As an extension from these reports, this paper introduces an effective application of the WTPI technology to the safer and optimal power supply for battery charging or the like for electric vehicle and any battery-driven mobile robot systems. In this paper, effectiveness of the proposed closed-loop charging through the WTPI coupling is highlighted. For the practical application of the proposed charging, the power transmission efficiency through the WTPI must be high, and the data transmission by way of the WTPI coupling needs to be bi-directional and fast enough for the real-time data feedback and charging control. By analyzes on the transmission performance using the equivalent circuits, the power transmission efficiency of about 92% and the data transmission bandwidth of 8.5 Mbps are obtained with the practical WTPI coupling configuration. The charging condition is optimized, according to the proposed estimation of the residual battery capacity. As a result, the time for completion of charging is minimized by 30% and the life of the battery is elongated by 20%. Index Terms--Closed-loop optimal battery charging, residual capacity estimation, wireless transmission of power and information.