Research On New Asymmetrical Half-Bridge DC-DC Converters

DC-DC converter is carried out by high-speed circuit control switch opening and closing to change the DC or AC power into the required voltage of one or more groups of devices. With the development of the modern electronic technology, the demands for the high performance of switch power are escalated exponentially, And switch power supplies have been widely used in almost all the electronic equipment.The DC-DC converter is one kind style of power supply convention, which transform one DC power into anther or more DC power. The circuit topology and control method are the chief problem in the power research, which are the key points in the power technology. As the traditional converters have many shortcomings:lower frequency of switch power, high power losing, complex circuit organization, and large size, which are difficult to meet the demand of the power technology. In accordance with the requirement of the switch power, a new asymmetrical half-bridge DC-DC converter is presented in this paper.The new asymmetrical half-bridge converter is introduced in this thesis, which has an assist switching tube and a branch circuit consist of diodes to achieve ZVS for the main switch and eliminates non-linear control characteristics and the transformer shortcomings of DC bias.Based on the electric current control method, the small signal model of new asymmetrical half-bridge converter is researched in this paper. And the control circuit of converts, the cancelling circuit, the power circuit, the protective power circuit, the current and voltage cascade circuit, and the drive circuit are designed. Finally, the simulation study of the converter is given with the designing parameters. The experimental results have demonstrated that the stability of the proposed system is improved with slope compensation. And the dynamic response speed of the current mode control method is better than the voltage mode controller.