本质安全Boost变换器的非爆炸内部本质安全判据

Non-explosive inner-intrinsic safety criterion of intrinsic safe boost converter

为了得到本质安全Boost变换器的非爆炸内部本质安全判据,提出了一种将Boost变换器的电感分断放电特性等效为简单电感电路的分析方法——等效电阻法.根据变换器电感分断火花试验在开关导通和关断时的等效电路,推导出输出电压变化的递推关系式.应用单一线性衰减模型和迭代法,得出电感分断放电的电弧持续时间和输出电压变化量,从能量等效的角度得出等效简单电感电路的等效电感电流.指出流过变换器的电感电流远小于所对应的引燃电流时,电感分断也会引燃爆炸性气体,并且其引燃能力与输出电容有关.得出了Boost变换器的非爆炸内部本质安全判据.实验结果验证了所提出的判断方法的可行性和理论分析的正确性.

To obtain non-explosive inner-intrinsic safety criterion of boost converters, an equivalent-resistance-analysis method was proposed. The Inductor-Disconnected Discharged （IDD） process of an Intrinsically Safe Boost Converter （ISBC） was converted into that of a mirror Equivalent Simple-Inductive-Circuit （ESIC）. A recursion formula of the output voltage was deduced according to the equivalent circuits of the converter in case of power switch turned on and off, respectively. The arc discharge time and output-voltage change during the IDD process were obtained, respectively, by using simple current linear attenuation model and an iteration approach. Based on the energy equivalent equation, the equivalent inductor-current of the ESIC was obtained. It is indicated that ignition occurs even when the inductor-current of boost converters is much lower than the known ignition threshold and that the ignition ability is strengthened with increasing of output capacitance. Based on above achievements, a new non-explosive inner intrinsic safety criterion of the ISBC is suggested. The results of experiments show that the proposed criterion is feasible.