基于STM32的大功率超声电源的研究

油田近井处理需要的大功率超声电源具有容量大、频率稳定、输出功率因数高的特点。在实际应用中,为了有效地将井内激发的大功率超声振动能量通过套管井的井内液体、套管和水泥环送入声学参数不同的地层,套管井的声学参数需要随时测量,作业参数需要实时调整。为此,选择了数据处理功能比较强的STM32单片机。基于其精确的定时器实现脉冲宽度调制（Pulse Width Modulation,PWM）输出,提供IGBT工作所需的波形;用其双路A/D同时采集作业时的电流和电压波形;用数字信号处理的方法快速处理电压和电流波形的相位差及幅值比,以此为基础调节发射波形的频率,使其与套管井条件下探头的谐振频率一致,实现频率跟踪和有效激发;借助于理论模型进一步处理电压和电流波形,获得套管井条件下的声阻抗,以便监测作业过程中套管井的声阻抗变化。

Study of STM32 based high-power ultrasonic power supply

The high-power ultrasonic power supply needed by former oil well processing near borehole zones has the characteristics of large capacity,stable frequency and high output power factor.In actual work,in order to send the high power ultrasonic vibration energy,which is stimulated in the well,into different strata with different acoustic parameters through the well fluids,casing and cement of the cased well,the key parameters of the system need to be real-time measured and the related parameters need to be adjusted in real time.To meet these needs,the MCS STM32 is selected as the core of the system.Based on its precise timer,PWM output can be realized so as to provide waveform which makes IGBT work;Using the method of digital signal processing,MCS STM32 can automatically process the phase difference and amplitude ratio information of current and voltage waveforms,which are collected by STM32’s dual AD converter at the same time.Taking this as the foundation,we can adjust the frequency of the transmitted waveform to the resonance frequency of probe.Ultimately frequency tracking and effective stimulation can be realized.Moreover,with the help of the theoretical model,we can obtain the acoustic impedance in cased well from further processing of voltage and current,so that the acoustic impedance change during the actual work can be monitored.