宽频开尔文电桥的屏蔽防护研究  

Shielding Method for a Resistance Comparison Bridge of Wide Frequency Range

作　　者：黄璐[1] 李正坤[2,3] 张钟华[4] 赵伟[1] 

机构地区：[1]清华大学电机系电力系统国家重点实验室 [2]西安交通大学电气工程学院 [3]中国计量科学研究院,北京100013 [4]中国计量科学研究院

出　　处：《电测与仪表》2006年第5期25-28,共4页Electrical Measurement & Instrumentation

摘　　要：工作频带很宽的电桥中,屏蔽防护问题较为复杂。由于作为电桥供电电源的数字信号发生器和作为指零仪的数字锁相放大器两者的对地寄生耦合以及环境电磁场等影响,导致宽频精密双臂交流电阻电桥的平衡很难调节。采用光隔离装置、电池供电的全自动正弦波发生器、电桥整体屏蔽及华纳接地等措施,有效解决了上述问题。结果,在10Hz～100kHz频率范围内,所构建的开尔文电桥的准确性优于10-5量级。In the alternating-current Kelvin double-resistance comparison bridge with wide frequency range, a digital generator and a lock-in amplifier are used as the signal source and the detector. The parasitic coupling between instruments and the ground, as well as the disturbance from the electromagnetic field, bring the difficulty in balance of the bridge. To solve these problems, an optical isolator, a full automatic sine wave generator with battery power, a metal shielded facility, Wagner earth device and other isolating measures are applied. The uncertainty of the measurement results with the bridge is better than 10-5 in the frequency range from 10Hz to 100kHz.

关 键 词：数字锁相放大器 微型继电器 文氏电桥振荡器 光隔离 

分 类 号：TM938.4[电气工程—电力电子与电力传动]