Hard- and Soft-Switched
Technical Dialogue Session
DC-DC Converters I
Four-switch buck-boost, ZVS, minimum freewheeling current, efficiency optimization.
A control method to achieve the minimum freewheeling current for the four-switch buck-boost (FSBB) converter is presented in this digest. Compared with the conventional method, the proposed method can make the best use of the energy stored in the junction capacitance of the boost stage to realize ZVS of the buck stage. Therefore, the soft-switching can be realized under the condition of the minimum freewheeling current. Based on the ZVS analysis, the minimum freewheeling current and the dead-time under different input conditions are determined. Moreover, the sampling circuit and the control parameter of the proposed method are also illustrated.