医疗供电系统绝缘电阻交流脉冲变频测量

在特殊医疗场所,为保证供电的连续性和降低故障漏电流,供电系统必须采用中性点不接地系统(IT系统)供电并配置绝缘监测仪用来监测电网对地的绝缘电阻.针对现有绝缘电阻测量方法精度不高,控制结构复杂的特点,提出了绝缘电阻交流脉冲变频测量法.通过±12 V交流脉冲电压的注入,在分析测量原理的基础上,阐述了绝缘测量的硬件设计和稳态判断的算法实现.对测量电阻两端的压降和号调理电路进行PSpice仿真,并对样机进行检测证明,绝缘电阻测量误差和测量范围符合预期的目标.

Alternative Pulses Measurement with Variable Frequencies for Insulation Resistor in Medical Power Supply System

Power supply system with neutral point unearthed or IT system,and insulation monitoring are applied to special medical facilities to provide continuous electric source and reduce leakage current of fault.A new way,alternative pulses with variable frequencies,to measure insulation resistor is presented,while traditional methods are either low accuracy or with complicated control systems.The hardware design and program chart of stable case are discussed based on the analysis of measurement principle and the injection of alternative pulses with plus or minus 12 V.The software PSpice is supposed to simulate both voltage-drop of insulation resistor and signal conditioning circuits.After sample verification of insulation resistor,both measurement tolerance and range of insulation resistor meet previous measurement expectations.