基于测差原理的直流电流传感器校准技术研究

Research on the calibration technology of direct current sensor based on the difference measurement principle

直流电流传感器将输入电流按比例转换为输出电流,比例误差是其重要的技术指标,误差值的确定是直流电流传感器合理使用的关键环节之一。传统的源表法所用商业仪器技术指标无法满足高准确度直流电流传感器(最大允许误差10;量级及以上)的校准要求。提出一种基于测量二次侧差值电流的原理,根据不同的被校比例参数特点,运用自校法、对校法和级联对校法,以标准直流电流比例值为参考,得到被校直流电流比例的实际值和误差。该测差原理降低了测量仪器的指标限定,同时减小了不确定度,满足直流电流比例类仪器的校准要求。

Direct current sensor converts the input current into a proportional output current. The ratio error is an essential specification, the error value determination is one of the key links in the rational use of direct current sensor. The specification of commercial instruments employed in the traditional source meter method failes to meet the calibration requirements of high accuracy direct current sensor(maximum permissible error 10;magnitude and above). A principle based on the measurement of secondary side difference current is proposed. According to the characteristics of the calibrated ratio parameters,taking the standard direct current ratio value as the reference,the actual value and error of direct current ratio are obtained by employing self-calibration method,equal-ratio calibration method and stage-connection equal-ratio calibration method. This measurement principle reduces the index limit of instrument and the uncertainty at the same time;satisfies the calibration requirements of direct current ratio instruments.