The Asymmetrical Half-bridge Converter Based On Two-transformers

In today’s society, high efficiency and high power density is an important goal of the pursuit of power electronic devices. The asymmetrical half-bridge converter has been widely used in low and medium power applications for its advantage in soft-switching achieving with no elements adding. However, the duty cycle loss problem and the duty ratio limit problem in traditional asymmetrical, affecting the operation efficiency and limiting the input voltage range. What’s more, the voltage stress across the output rectifier diodes is not balanced. Aiming at the above problem, the asymmetrical half bridge converter based on two-transformer is produced to improve the performance of converter.This design analysis the steady-state and transient operation of the asymmetrical half-bridge converter based on two-transformer. The reason of improving the duty cycle loss problem, solving the duty ratio limit and balance the voltage stress of the rectifier diodes is illustrated. The transfer process of the energy of the converter is explored. The condition of the soft-switching is deduced.The large signal and small signal modeling of the converter is derived. The model is simplified in math method. The factors influencing the model are analyzed.The closed-loop system of the converter is established by the peak current control method with a Ⅲ compensator. The comparing of the simulation of the traditional converter and the converter based on two-transformers to verify the advantages of the converter based on two-transformers. The simulation of the dynamic performance is established.The power circuit, control circuit, feedback circuit and the protection of the converter is built base on the analysis and the simulation of the converter. Then the working characteristics is verified. The converter has good switching characteristics and dynamic characteristic s.