Fig. 4.
Proposed dc/dc choppers (circuit breakers) with minimal number of active switches.
2.2. Operating principle of proposed topologies
The operating principle of proposed two-switch topology is shown in Fig. 5. During turn-on period, the active switches S1 and S4 are conducting and the energy is stored in dc inductor Ldc. The energy stored in Ldc is discharged to the load through D3 during turn-off period. The mode of operation considering continuous inductor current is shown in Fig. 5c. During one switching period Ts, the average dc voltage across the inductor is zero assuming a loss-less system:
equation(1)