A peak-shift control method for charging and discharging of the battery in an ultrabook

As the electricity rates during peak hours are higher, this paper proposes a method for an ultrabook to automatically shift the charging period to an off-peak period. In addition this design sets an upper limit for the battery which thus protects the battery and avoids its remaining in a state of continued high voltage. We use a low-power embedded controller (EC) as the main control part together with RTC ICs. The sensing value of the EC and the presetting of parameters are used to control the conversion of the AC/DC module. Our user interface design allows the user to set the peak/off-peak period and the upper limit of the battery. The design also controls dynamically both the charging current and the charging voltage, in accordance with the temperature of the battery. In this way our design extends the life of the battery.