利用计时器芯片和脉冲占空比调制的光电式电压传感器

An optoelectronic voltage sensor based on timer chip and pulse duration ratio modulation

提出一种利用计时器芯片和脉冲占空比调制的光电式电压传感器,用于测量直流高电压。利用计时器芯片ICM7555,可以将被测直流高电压转换为脉冲占空比调制信号,并驱动发光二极管(LED)产生脉冲光传感信号;利用单根多模塑料光纤将光传感信号传输到光电探测器及信号处理电路,即可获得光电传感信号,通过测量其脉冲占空比,即可解调出被测高电压。分别采用输出脉冲频率和脉冲占空比作为电压传感信号,实验测量了10 kV直流高电压,并比较分析了测量结果的相对误差。结果表明,采用输出脉冲占空比作为电压传感信号时,传感器的相对误差更小,此时测量结果的引用误差低于0.6%。

An optoelectronic voltage sensor based on a timer chip and pulse duration ratio modulation is proposed and investigated experimentally in order to measure direct current(dc)high voltage.The dc high voltage to be measured can be proportionally converted into the voltage sensing signals modulated by pulse duration ratio by use of the ICM7555 timer chip.The optical sensing signal is generated by a light-emitting diode(LED)which is modulated by the above pulse signal,and transmitted to a photo-detector and signal processing circuits through a piece of plastic optical fiber.The dc voltage sensing signal to be measured can be demodulated from the measurement of the output pulse duration ration.The comparison analysis of relative errors has been conducted for the sensing schemes respectively based on pulse frequency modulation and pulse duration ratio modulation,and relative errors are smaller for the duration ration modulation than those for the frequency modulation.The dc high voltage with amplitude of 10 kV has been measured experimentally,and the fiducial error of the experimental data is less than 0.6%.