IFEC 2018
System for Fast Battery Charging
Since traditional energy sources are almost completely depleted, power grids are intensively shifting their reliance onto renewables, such as biomass, wind and sun energy. The problem with wind and solar power plants is intermittency: the amount of produced power varies depending on the time of day or year and does not comply with the consumption needs. This sometimes results in generating excess energy, which is usually stored within specialized systems that consist of batteries and power converters. Therefore, the goal of this project was to create a bidirectional DC/DC converter for fast battery charging (and discharging) with galvanic isolation. Another requirement was high efficiency – a practical way to achieve the smallest possible dimensions of the device.
We incorporated a CLLC resonant converter into our 1000W system. This topology uses the resonant phenomena during transistor commutation to enhance energy efficiency. Design achieved the efficiency of 97% using the SiC MOSFET transistors. Four hundred volts are on the high voltage side, while low voltage ranges from 35 to 50V. Galvanic isolation of the device was attained by using a transformer, so that the device is protected from the high voltages.
