Back-up Switching Supplies with Energy Storage Capacitor and its Applications

To keep the automation terminal units working for a short period in case of outage, a back-up switching supply based on super-capacitor energy storage is proposed. The design considerations of the converterpsilas lowest-limit working voltage, the needed capacitance of the super-capacitor and the needed capacitance of the output capacitor are discussed. An example is given. The experiment results show the feasibility of the design considerations, with which, the indexes of back-up time, the maximum and minimum output voltages of the super-capacitor energy storage power supplies can be guaranteed. Applications of the super-capacitor energy storage power supplies in feeder automation systems, the distribution transformer monitoring systems and the situation when the polarity or the excitation positions a large DC current need to shift are also described as well.