高准确度交流电压标准源电路设计与实现

Design and implementation of high precision AC voltage standard source circuit

为满足交流电压参数校准验证的需求,本文设计了一种高准确度交流电压标准源电路。基于高准确度、高稳定性要求整体电路采用闭环反馈结构,使用AD9850芯片生成交流信号,通过直流参考电压对正弦波进行调幅,微控制器使用AVR芯片。同时信号模拟电路与数字控制电路实现电气隔离,通过硬件选型、软件补偿等措施提高准确度。设计输出量程范围1~10 V,输出频带40 Hz~100 kHz。交流电压标准源在典型频率点上多次测试,结果表明在频带40 Hz~50 kHz中输出满量程电压的允许误差小于0.006%;在100 kHz处满量程电压的允许误差保持在0.025%以内,电路具有准确度高、稳定性好等性能优点。

In order to meet the needs of calibration and verification of AC voltage parameters,a high precision AC voltage standard source circuit is designed in this paper.Based on the requirements of high precision and high stability,the overall circuit adopts a closed-loop feedback structure,uses AD9850 chip to generate AC signal,and then modulates the amplitude of the sine wave through the DC reference voltage.The microcontroller of the circuit uses AVR chip.At the same time,the signal analog circuit and the digital control circuit are electrically isolated,and the accuracy is improved through hardware selection,software compensation and other measures.The output range of the designed circuit is 1~10 V,and the output frequency band is 40 Hz~100 kHz.The AC voltage standard source is repeatedly measured at typical frequency points.The results show that the permissible error of the output full-scale voltage is less than 0.006%in 40 Hz~50 kHz,the permissible error of the full-scale voltage at 100 kHz is kept within 0.025%.The circuit has the advantages of high precision and good stability.