摘要
电容式油位传感器需要已知频率的交流信号激励才能正常工作,激励信号的频率精度和保真度直接影响采集结果的准确性。目前常用的激励方式的配置专用波形发生器产生指定频率的激励信号。然而,该方法硬件电路较复杂,可靠性较低,且需要配置专用晶振,明显增加了电磁干扰等风险。在此设计了一种结构简单、灵活性更强的现场可编程门阵列(FPGA),通过处理器单元向波形发生控制器指定寄存器中写入配置字实现发生波形的在线编程,波形发生控制器依据配置字实现相位合成和数字幅值信息的产生,数模转换单元实现数字幅值信息到电压信号的转换。与AD9837专用波形发生器的比较实验结果表明,在0~5 MHz范围内的正弦波产生过程中,所提方法所发生信号的频率精度和保真度有显著提高,当发生信号的频率为10 kHz时,频率误差降低了85.92%,失真度降低了56.59%。
AC excitation is essential for capacitive oil level sensors and its accuracy and fidelity affect the accuracy of the acquisition results directly.The currently used excitation method is to set a dedicated waveform generation chip.However,this method has obvious disadvantages of high complexity,low reliability and enhanced electromagnetic interference caused by the dedicated crystal oscillator.A programmable excitation generation circuit with simple structure and more flexibility is designed.And it realizes the online programming by writing the configuration words to the specified register of the waveform generation controller in the field programmable gate array(FPGA).Waveform generation controller realizes phase synthesis and digital amplitude information extraction.And the digital-to-analog conversion unit generates voltage signals according to the digital amplitude information.Compared with the AD9837 which is a dedicated waveform generator,the results show that the frequency accuracy and fidelity of the signal generated based on our method are significantly improved among the range of 0-5 MHz.When the frequency of the generated signal is10 kHz,the frequency error is reduced by 85.92% and the distortion is reduced by 56.59%.
作者
屈盼让
呼明亮
孙少华
蔡晓乐
QU Pan-rang;HU Ming-liang;SUN Shao-hua;CAI Xiao-le(AVIC Computing Technique Research Institute,Xi'an 710065,China)
出处
《电力电子技术》
CSCD
北大核心
2020年第4期53-56,共4页
Power Electronics
关键词
可编程激励源
航空油量采集
频率误差
失真度
programmable excitation generator
aviation fuel quantity acquisition
frequency error
distortion
