一种DC-DC变换器开关管故障在线诊断与容错方法

Online fault diagnosis and tolerance method for DC-DC converter switch

针对DC-DC变换器中开关管故障诊断问题,提出一种将DC-DC变换器中磁性元件的电压在特殊时刻的逻辑值作为故障信号的开关管故障在线诊断与容错方法。根据DC-DC变换器分别在连续和断续两种工作模式下磁性元件电压与变换器不同工作状态之间的对应关系,可得在开关管发生短路或开路故障时,磁性元件的电压与DC-DC变换器正常工作时不同,因此选取开关管在一个开关周期内两个特殊时刻(开关管在导通期间的中间时刻和关断的期间的中间时刻)磁性元件的电压逻辑值为故障信号,设计故障检测与诊断系统。该方法可在线检测识别开关管短路与开路故障,具有成本低、在线的优点。根据检测识别结果,设计了容错电路,有效提高了变换器可靠性。通过仿真和实验结果,验证了该方法的准确性和有效性。

Aiming at the fault diagnosis problem of switch in DC-DC converter,a method of on-line faulted diagnosis and tolerance of power switch with the logic value of two time point of the magnetic component in DC-DC converter as the fault signal is proposed.According to the correspondence relation between the magnetic component voltage and different working states of DC-DC converter in the continuous and intermittent operation modes,the voltage logic of the magnetic component value of two special time points(the middle time of the switch turn on and off)in one cycle was selected as the fault signal,and the fault detection and diagnosis circuit is designed.The method can detect and identify short circuit and open circuit fault of switch online,and has advantages of low cost and real-time performance.According to the detection and recognition results,a fault tolerant circuit was designed to effectively improve the reliability of DC-DC power system.The accuracy and effectiveness of the proposed method is verified by simulation and experiments.