Energy-Limited Transient-Mode Fast Supercapacitor Charger Topology

Electric double-layer capacitors, commonly known as supercapacitors (SC), provide excellent energy storage solutions to short-term high-power requirements. Compared to a typical dc-dc converter with a resistive load, SC charging circuits do not have to supply a continuous dissipative load. A capacitor charger's operation is defined by the maximum charge to be stored in the capacitor bank. To achieve a practical energy-limited fast SC charger, a new circuit topology is proposed where the SC bank is divided into two parts. One is charged by an overrated voltage source with capacitor terminal voltage monitoring, and the other is charged from the energy stored in a coupled inductor. This letter provides an overview of the concept together with experimental and simulation results for two 100-F, 15-V SC banks with 3-W·h rated energy storage.