Super-capacitor voltage equalization technology based on zero-voltage switching

In order to reduce the switching loss of the switching devices during the switching process of super capacitors, and to improve the efficiency of voltage equalization and energy utilization, a novel type of super capacitor voltage equalization circuit based on zero voltage switching (ZVS) is proposed. Details of the operation principles were introduced, relationship of voltage and current in different work process was analyzed. A time domain model of voltage and current of the circuit was found, and the effects of different parameters on the working characteristics of the circuit was analyzed, the principle of designing key parameters of a new type of voltage equalization circuit was given, zero voltage switching condition was obtained by calculation, using the diagrammatic representation of zero voltage region. The simulation and hardware experiment were implemented. Results show that the method realizes real zero voltage switching process, the efficiency of the equalization method is more than 80%, and switching loss decreased by 75%, which reduces the switching loss significantly and is suitable for the series super-capacitors or batteries in energy storage system. Based on the general topology model of multilevel converter, the circuit can be expanded and convenient for applications in large-scale storage system, which is widely used in electric power systems, new energy and other fields, with a high value and great prospects for development.