Abstract:

According to the problem that cell voltage imbalance of series connected super capacitor in energy storage system, this paper presented a voltage-balance circuit for super capacitors in a half-bridge inverter based on the sequence coupling array integrated magnetic method.Sequence coupling method was used in secondary winding of converter to achieve voltage balance of monomer, which can reduced voltage unbalance caused by leakage error in transformer. The circuit topology is simple, and can automatically balance super capacitor voltage ,feedback control can be eliminated when the system is operated with a fixed switching frequency and duty ratio. By analyzing the each working mode of half-bridge converter, established the output voltage equations,and the super capacitor voltage balance equation. According to the circuit characteristics, analyzes the design equation of the transformer turns ratio,and the leakage inductance of the transformer primary to achieve soft switch。The simulation and experimental results show that this equalizing circuit has both speed and pressure equalizing good features.

Key words: Half-bridge inverter, sequence coupling transformer, super capacitor, voltage equalization