航磁用无人机正激变换器的优化设计

Optimized Design of UAV Forward Converters in Aeromagnetic Survey

针对航磁用无人机采用开关电源作为其动力来源,正激变换器在功率开关管关断时会产生瞬时电压尖峰,在航磁用无人机设备中会引起较宽频带的电磁干扰,正激变换器复位时,复位电压平台值过高会严重影响功率开关管的使用寿命.首先对正激变换器变压器的磁路进行了分析,从原理上阐述了开关管关断时瞬态尖峰脉冲形成原因,给出了并联电阻电容(resistors and capacitors,RC)支路的作用和各元件的取值方法;在此基础上,设计了电阻、电容和二极管(resistor,capacitor,and diode,RCD)谐振复位电路,将开关管关断时产生的尖峰脉冲控制到了合理的范围,降低了复位电压平台值,保证了开关电源长期可靠的运行.实验结果证实了理论分析的正确性.

Switch mode power supply is a good selection for UAV. The forward converter will generate transient voltage spikes when the power is switched off and cause wide-band electromagnetic interference with a continuous spectrum. The higher level of the resonant reset will destroy the metal-oxide-semicondutor field-effect transistor （MOSFET）. This paper analyzes the magnetic field of the forward converter transformer, explains the reasons in forming voltage spike of the MOSFET, designs a RC branch in parallel to the magnet, and presents a way to select the parameters of the component. To guarantee the long-term operation of the switch, the resistor, capacitor, and diode （RCD） resonant reset circuit is designed. The experimental results agree well with the analysis conclusions.