开关变换器的本质安全特性分析与设计

Intrinsically Safe Behavior of Switching Converters and Its Design

通过分析开关变换器的最危险故障状态,得出了判断其内部本质安全的等效电感电路。根据开关变换器的最大输出短路释放能量,得出了变换器的输出短路等效电容。以电容、电感电路的点燃曲线作为依据,得出了开关变换器内部和输出本质安全的判断方法。以变换器同时满足本质安全和期望的输出电压纹波要求作为限制条件,得出了电感、电容的设计范围。以Buck变换器为例进行了分析和试验,结果验证了所提方法的可行性和理论分析的正确性。

The equivalent inductive circuit of switching converters for checking its inner-intrinsic safety is obtained by analyzing the most dangerous case in various operating mode. The maximum output short-circuit discharged energy is deduced, and the output equivalent capacitance of switching converters is obtained. The inner-intrinsic safety of a switching converter is determined by comparing the maximum current of the inductor of the converter with the minimum ignition current. The output intrinsic safety is identified by minimum ignition voltage curves for capacitors. The design region of inductance and capacitance is obtained in accordance with the requirements of intrinsic safety and the desired output voltage ripple level. Experiments are made on a Buck DC-DC converter. The results show that the analysis is right and the proposed methods are feasible.