Translated Abstract
With the development of electron in the information and consume, the demand on the power is becoming more and more versatile. Miniaturization, lower cost and high reliability are the trends of electron equipment, which need the power lower profile and high efficiency. To complete that purpose the power needs to work at higher frequency, but the high frequency can result in higher switching loss in transformer and MOSFET etc. To decrease the component loss, the research on the soft switching technique is popular. The paper analyzes the present situation, the development of high frequency switching mode power supply and the soft switching technique, then to know the asymmetrical half-bridge (AHB) suits to be used in the medium power situation. The paper firstly emphasizes on the AHB converter’s steady state operation principle and the relationship between the input and output voltage, then bring forward the voltage and current pressure of some important components and the condition to realize the MOSFET’s ZVS and then considering the problem of transformer offset magnetizing current and the voltage oscillation in the circuit resulting from the inductor which in serial with the transformer, the paper analyses the reasons and the methods to resolve it. To the offset magnetizing current, it can be better through adjusting the circuit parameter or resolves in series with capacitor in double current rectify circle, but to the voltage oscillation it can be resolved by clamping the inductor to the source or ground. At last, the simulation proves the methods right.On that base, the paper provides the design method of some important components such as the transformer etc., and the simulation and the pattern (5V, 10A) prove the result of the hardware design. The paper concentrates on the circuit’s math model. From the model, we can find the circuit is instability and its dynamic response is slow. The paper resolves the problem of instability through compensating the circuit in frequency, and the simulation proves the method is effective. Through analyzing the AHB all-around, we know the AHB has some advantages such as: easy to realize the ZVS and the low voltage pressure of MOSFET etc. but because of the particularity of itself, the AHB can only be used in some special situation.
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