| Unmanned aerial vehicle (UAV) , can complete the complex flight tasks and various load jobs in unmanned condition, because it can effectively reduce the casualties, improve reconnaissance and combat flexibility and mobility, so that it currently has been highly valued as an important branch of unmanned combat system,playing a more and more important role in information warfare. The platform is composed of UAV flight control system, navigation system, control and information transmission system, power supply system and task load etc.. A large number of airborne electronic equipments equipped with the platform need stable and reliable power supply system, so the stability of airborne power system directly affects the working state of airborne equipment and flight safety.Therefore, it is of great practical significance to develop a switching power converter with high efficiency, high power density and high reliability for the UAV application environment.This paper mainly from the following aspects of research and design work:1. For wide input voltage range of high-power switching power supplyto study the composition and influence factors of loss of SMPS, and compared with the disadvantages of single stage topology, focus research on the advantages of Buck+"Half bridge - staggered forward" two cascaded topology and develop the unit circuit exclusively, wide input voltage up to 155V to 425V.2. Airborne 270V high voltage DC bus power supply system has the characteristics of large transmission power, high efficiency, and high reliability, can significantly reduce the bus current, improve efficiency, and reduce electromagnetic interference.However, the design of auxiliary power supply for DC/DC high voltage power supply module used in 270V DC bus is a difficult problem. Wide range of input voltage can inhibit the rapid fall of the input voltage when voltage power supply is high, so that the auxiliary power supply can response rapidly to maintain stability.3. The traditional high voltage MOSFET driver is mainly worked by bootstrap,transformer coupling and high voltage driver, but there are many disadvantages, such as large delay time, complex circuit and large occupied area. The technical scheme of theproject intends to use Digital Isolator and Low voltage driver combination, to make electrical isolation between input and output connection, eliminate the adverse effects of the ground loop, increase CMRR, and enhance the driving capability of the driving signal, realizing direct drive, suspension main switch MOSFET and electric circuit design of MOSFET with convenient design and simple principle.4. High current load and redundant power supply module must have a parallel flow function, the conventional parallel flow technology can only achieve flow control accuracy, usually do not have power on synchronous startup and fault unit automatically exit function. Digital frequency discrimination and fast lock-in technique based on synchronous start stop can realize multi module; and to ensure that a plurality of power supply modules can be synchronized in a small range of its own frequency, while the external frequency discrimination, avoid high switching frequency of the switch loss increases and reducing efficiency.5. Using the method of mixed control, can realize various high density protection functions, under the premise of the lower line design complexity and using a single chip microcomputer as online detection unit, to ensure the safety and reliability of the circuit. |
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