单—双相压电泵及驱动控制系统研究

发布时间：2018-08-20 14:42

【摘要】：压电泵可通过电信号精确控制流体输出,并且体积小,能耗低,无电磁干扰,工作噪声低,在生物医疗、化学分析、芯片冷却、喷墨打印等方面具有广阔前景,是目前微流体领域研究的热门课题。目前研究人员在压电泵结构方面进行了深入具体的研究,而在压电泵驱动、控制方面的研究相对较少,无法充分发挥出压电泵在流体输送精密控制方面的优势,因此对该方面进行研究显得十分迫切。本文结合教育部高等学校科研创新重大培育资金项目及国家自然科学基金项目,围绕单双相压电泵系统,开展了结构设计、专用驱动电源研制、输出性能测试、流量自测量及液体输送精密控制方面的工作。 1.泵用压电振子性能分析及测试压电振子是单双相压电泵核心驱动部件,利用Butterworth Van Dyke等效电路模型,分析直径为35mm的泵用双晶片压电振子阻抗特性,对压电振子阻抗特性进行测试,找出压电振子一阶共振频率,并计算出对应的阻抗模；对圆形双晶片压电振子变形能力进行试验研究,分别测试压电振子表面各点变形位移,压电振子中心位移与驱动电压、驱动频率的关系,为压电泵的结构设计及驱动电路设计奠定基础。 2.单双相压电泵的设计研制分析单、双相压电泵,包括单腔单振子压电泵、双腔串联压电泵、双腔并联压电泵、主被动阀结合泵、双主动阀压电泵的工作原理,推导单腔单振子压电泵输出能力与压电振子结构参数、材料性能参数、驱动信号参数间关系,分析主动阀结构参数对工作性能的影响。分析表明与单腔单振子压电泵相比,双腔串联压电泵具有更大的输出压力,双腔并联泵具有更大的输出流量；对双腔串联压电泵、双腔并联压电泵来说,异步驱动方式比同步驱动方式具有更好的输出性能；双主动阀压电泵中具有更宽的工作频率范围,并可实现液体双向输送,具有独特的输出性能。制作单双相压电泵样机,为驱动控制的研究提供载体。 3.压电泵专用驱动电源研制在对压电泵驱动信号分析基础上,以单双相压电泵为驱动对象,研制三种专用驱动电源：模拟式单相压电泵驱动电源、程控式单相压电泵驱动电源及数字控制式双相压电泵驱动电源。分析驱动电源系统及各部分电路工作机理。对研制的压电泵驱动电路电气输出性能进行测试。研制的三种驱动电源,输出电压均可在0V到最大值之间调节,最大输出电压不小于170V；输出频率可在5Hz-500Hz之间调节,其中模拟式单相压电泵驱动电源体积小、成本低廉。程控式单相压电泵驱动电源可通过按键对输出参数调节,避免电位器接触不良带来的影响,提高了电源信号输出的可靠性及稳定性；数字控制式双相压电泵驱动电源利用直接数字式频率合成技术,可输出两列有严格相位关系的正弦信号,相位差可在00-360。范围内调节,相位差最小分辨率为11.25。,采用数字化控制,输出参数实时显示。研制的三种驱动电源输出参数能够独立、连续调节,可以灵活方便地对压电泵进行驱动控制。 4.单双相压电泵输出性能试验研究利用研制的数字控制式双相压电泵驱动电源,对单双相信号驱动的压电泵输出性能进行试验研究,研究泵输出流量、输出压力与驱动电压、驱动频率、相位差之间的关系。可知对于双腔串联泵,异步驱动比同步驱动具有更好的频率适应性及更大的输出流量,工作频率范围为10Hz-400Hz,最大输出流量为94.174mL/min,并且输出压力变动幅度小。对于双腔并联压电泵,异步驱动方式下具有更好的输出性能。双主动阀压电泵具有较宽的工作频率范围,从10Hz到220Hz,通过改变驱动信号间的相位差,可改变液体的流动方向及流量大小,与本文研制的其它压电泵相比,具有独特输出性能。 5.基于压电自感知的单腔单振子压电泵流量自测量方法提出一种利用压电自感知功能的压电泵流量自测量方法。对流量影响因素及传感压电信号与压电振子变形关系进行分析,得出传感压电信号特征参数与泵流量有明确对应关系,在传感压电信号中隐含着压电泵流量信息。研制用于流量自测量的传感压电信号参数测量电路样机,并构造用于压电泵流量预测的BP神经网络模型,该神经网络以电压参量、频率作为输入参数,得到流量的预测值。对提出的流量自测量方法进行试验验证,结果表明预测值与试验测量值之间的相关系数在0.9993以上,最大相对误差率小于3.46%。该流量自测量方法具有较好的准确性。并且该流量自测量方法还可以应用到其它类型、结构的压电泵中。 6.基于定脉冲数的液体输送精密控制方法在对压电泵驱动特点及输出性能分析基础上,进行基于定脉冲数的液体精密输送控制方法研究。研制定脉冲数控制电路,对基于定脉冲数的液体输送精密控制方法进行试验验证。试验结果表明,在不同的脉冲数下,压电泵输送液体体积具有良好的线性比例关系,最大相对误差为0.424%,相关系数为0.9999,表明基于定脉冲数的液体输送精密控制方法具有可行性。因此在流体输送量精度要求较高的场合,可以根据输送体积,求出对应的脉冲数,向压电泵发送脉冲,实现流体的精密输送控制。
[Abstract]:Piezoelectric pumps can accurately control the output of fluids through electrical signals, and have small volume, low energy consumption, no electromagnetic interference, low noise. They have broad prospects in biomedical, chemical analysis, chip cooling, inkjet printing and so on. They are hot topics in the field of microfluids. At present, researchers have conducted in-depth study on the structure of piezoelectric pumps. In this paper, the research on the piezoelectric pump drive and control is relatively small, which can not give full play to the advantages of the piezoelectric pump in the precise control of fluid delivery. Therefore, it is very urgent to study this aspect. Structural design, development of special driving power supply, output performance test, flow self-measurement and precise control of liquid conveying have been carried out.
Performance analysis and test of 1. piezoelectric vibrator for pump
Piezoelectric oscillator is the core driving component of single-phase and dual-phase piezoelectric pump. Using Butterworth Van Dyke equivalent circuit model, the impedance characteristics of bimorph piezoelectric oscillator for pump with a diameter of 35 mm are analyzed. The impedance characteristics of bimorph piezoelectric oscillator are tested. The first-order resonance frequency of the piezoelectric oscillator is found and the corresponding impedance modes are calculated. The deformation ability of the piezoelectric oscillator is tested by experiment. The relationship between the displacement of the center of the piezoelectric oscillator and the driving voltage and the driving frequency is tested, which lays a foundation for the structure design and the driving circuit design of the piezoelectric pump.
Design and development of 2. single phase dual phase piezoelectric pump
The working principle of single-cavity piezoelectric pump and dual-phase piezoelectric pump including single-cavity single-oscillator piezoelectric pump, double-cavity series piezoelectric pump, double-cavity parallel piezoelectric pump, active-passive valve combination pump and dual-active valve piezoelectric pump is analyzed. The relationship between output capacity of single-cavity single-oscillator piezoelectric pump and structural parameters of piezoelectric oscillator, material performance parameters and driving signal parameters is deduced. The analysis shows that the output pressure of the double-cavity piezoelectric pump is higher than that of the single-cavity single-oscillator piezoelectric pump, and the output flow of the double-cavity parallel pump is larger. The valve piezoelectric pump has a wider working frequency range and can realize liquid two-way transmission. It has a unique output performance.
Development of special driving power supply for 3. piezoelectric pump
Based on the analysis of driving signal of piezoelectric pump, three kinds of special driving power supply are developed, which are analog single-phase piezoelectric pump driving power supply, program-controlled single-phase piezoelectric pump driving power supply and digital control dual-phase piezoelectric pump driving power supply. The electrical output performance of the piezoelectric pump driving circuit is tested.
The output voltage of the three kinds of driving power supply can be adjusted from 0V to the maximum value, the maximum output voltage is not less than 170V, and the output frequency can be adjusted between 5Hz and 500Hz. Among them, the analog single-phase piezoelectric pump driving power supply is small in size and low in cost. The reliability and stability of the power supply signal are improved by the bad contact of the positioner. The driving power supply of the digital controlled dual-phase piezoelectric pump can output two series of sinusoidal signals with strict phase relationship by using the direct digital frequency synthesis technology. The phase difference can be adjusted in the range of 100-360. The minimum resolution of the phase difference is 11.25. With digital control and real-time display of output parameters, the output parameters of the three driving power supply can be adjusted independently and continuously, and the piezoelectric pump can be driven and controlled flexibly and conveniently.
Experimental study on output performance of 4. single phase biphase piezoelectric pump
The output performance of piezoelectric pump driven by single-phase and double-phase signals is studied experimentally by using the developed digital control driving power supply of dual-phase piezoelectric pump. The relationship between output flow, output pressure and driving voltage, driving frequency and phase difference is studied. And larger output flow, operating frequency range from 10Hz to 400Hz, the maximum output flow rate is 94.174mL/min, and the output pressure variation is small. Compared with other piezoelectric pumps developed in this paper, it has unique output performance.
5. self sensing method based on piezoelectric self sensing method for single chamber single oscillator piezoelectric pump flow measurement
A flow self-measurement method of piezoelectric pump based on piezoelectric self-sensing function is proposed. The flow influencing factors and the relationship between sensing piezoelectric signal and deformation of piezoelectric oscillator are analyzed. It is concluded that the characteristic parameters of sensing piezoelectric signal correspond to pump flow clearly. The flow information of piezoelectric pump is hidden in sensing piezoelectric signal. The self-measured piezoelectric signal parameter measuring circuit prototype is constructed, and a BP neural network model for flow prediction of piezoelectric pumps is constructed. The neural network takes voltage parameters and frequency as input parameters to obtain the flow prediction value.
The experimental results show that the correlation coefficient between the predicted value and the measured value is above 0.9993, and the maximum relative error rate is less than 3.46%. The flow self-measuring method has good accuracy, and the flow self-measuring method can also be applied to other types and structures of piezoelectric pumps.
6. precise control method for liquid delivery based on fixed pulse number
Based on the analysis of driving characteristics and output performance of piezoelectric pump, the control method of liquid precise conveying based on constant pulse number is studied. The pulse numerical control circuit is developed and the precise control method of liquid conveying based on constant pulse number is tested and verified. The maximum relative error is 0.424%, and the correlation coefficient is 0.9999. It shows that the precision control method of liquid conveying based on the fixed pulse number is feasible. Therefore, in the case of high precision of fluid conveying, the corresponding pulse number can be calculated according to the conveying volume, and the pulse number can be sent to the piezoelectric pump to realize the fluid conveying. Precision conveyor control.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TH38;TP273

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