Research On Anti-short-path High Reliable Topology And Control Stratege

The aerospace power converter plays a critical role in the aerospace craft system. It brings the development of aerospace power great difficulty because of the particularity of space environment and the un-maintainability of the power supply. With the development of space technology, higher requirement in the aspects of suitable for high input voltage,large power, high precision, is put forward. So high reliable topology, no short path, novel magnetic feedback technology, are researched in this paper based on this background.First, the basic power conversion cells, P-cell and N-cell, are analyzed. According to the theory of power flow reconstitution, a series of anti-short-path high reliable topologies are constructed. By comparing the characteristic of different topological structure analysis,a novel push-pull-half-bridge topology is chosen as the main circuit. The work principle is also deeply researched. UC3825 is chosen as the main control IC since it has mature technology in PWM control field. The converter works in constant voltage mode. Peak current control is applied. To solve the second-harmonic oscillation,emitter follower slope compensation is used. At the same time, surge suppression circuit, common-rejection circuit, drive circuit of MOSFET, are designed.In order to solve the effect of crossing coupling between the primary side and the second side, galvanic isolation must be achieved. The output voltage is regulated by using magnetic feedback technology. Three kinds of magnetic feedback technology are researched in this paper. Forward magnetic feedback scheme is applied after comparative analysis of different structure. Equivalent small signal model and hardware design is completed in the paper. The experimental index is tested after debugging。The prototype is successfully debugged. The efficiency reaches 89.8% at half load and 88.7% at full load. The experiment verifies the feasibility of the main topology and control strategy and provides reference for the design of aerospace power supply system.