100 V 输入宽频带电压比例校验系统研究OA北大核心CSTPCD

50 Hz～10 kHz voltage ratio calibration system based on digital acquisition device is proposed.The system is composed of voltage conversion unit and digital acquisition device.The channel switching technology is used to greatly improve the accuracy of voltage ratio with the digital acquisition device.The voltage conversion unit is composed of cascade inductive voltage divider,isolation transformer and high & low voltage precision voltage follower.In this part,the turn-back winding process and so on are proposed to reduce the additional error caused by the stray parameters and the iron core material,and a two-stage isolation transformer with twisted pair structure winding is designed.The amplitude error of the two-stage transformer within the 10 kHz range shall not exceed 5 × 10-6,and the phase error shall not exceed 10 μrad.Precise low-voltage and high-voltage composite voltage followers are designed to compensate the phase response by using the characteristic matching of the double-package operational amplifier,which significantly improves the phase characteristics of the voltage follower,within the 10 kHz range,the amplitude error of the follower shall not exceed 10 × 10-6,and the phase error shall not exceed 20 μrad.The measurement results indicate that the calibration system has high measurement accuracy,and the measurement deviation at 50 Hz is not greater than 1 × 10-6 and 1 μrad.Within the 10 kHz range,the ratio error deviation is not more than 80 × 10-6,and the phase error deviation is not more than 60 μrad,which can meet the voltage ratio error measurement requirements in different frequency scenarios.