Research On Wide Input Voltage Range DC/DC Converter

With continually increasing reliability demands of the power supply system for the modern aircraft, we need a new type of aircraft power supply system, of which the key is to develop a DC/DC converter with very wide input voltage range. In this paper, the system's high efficiency requirements is fully taken into account, we select two-stage DC/DC converter, the first stage is Boost pre-regulator, and the second is a multi-phase interleaved Buck converter used integrated magnetic technology.In the thesis's first part, it derives Boost converter's transfer function when the converter is operating in Continuous Conduction Mode(CCM). The transfer function includes a Right-Half-Plane(RHP) zero. Then we find out the mechanism of system stability under the influence of the RHP zero from two points of view—physical phenomena and control theory, and come to a conclusion that the inductance value affects the RHP zero's location and system stability. Boost converter is notorious for its difficult control loop stabilisation. Aimed at this problem, we give out a solution, then design compensation circuit for the converters whose transfer function include a RHP zero, and verified by experiments.In the thesis's second part, it analyzes the multi-phase interleaved technology. The uneven current sharing problem, affects the reliability of the system. So learning from master/slave current sharing technique, an improved current sharing method is proposed, and achieves good effect. In order to further reduce the size of magnetic components and achieve a good dynamic and static response, it analyzes the integrated magnetics'application in multi-phase interleaved converters. Then it study both direct coupling and inverse coupling inductors'influence to the ripple of inductor current and output current, and the dynamic response of converter. It also derives a equivalent circuit model of the integrated magnetics, and gives out the relationship of individual or coupling inductance and the magnetic's air gap. The relationship is suitable for the design of the magnetic core.Finally, it designs a multi-phase interleaved Buck converter, as well as the main circuit parameters and the current sharing control loop parameters, and verified by experiments.