Comparison of charging methods of multilevel hybrid energy storage for electromagnetic launch

Three charging methods, the DC chopper, the invariable voltage and the step voltage were analyzed in this paper. They were compared from the work principle, facilitys guide line, efficiency and ripple. Then the simulation models were constituted. The theoretical derivation and simulation results show that the efficiency of the step voltage arrives 0.911, which is better than the 0.5 of the invariable voltage. The guideline for the step voltage is n times lower than that for the DC chopper and it can confine the current ripple in 16% or even better with no increasing in switch waste. The experiment was conducted on a multilevel hybrid energy storage swatch for step voltage method. The result matches the simulation result well. So we get conclusion that the step voltage is the best method for the multilevel hybrid energy storage device.