基于频率自动跟踪与振幅恒定控制的超声电源的研制

发布时间：2018-03-30 18:21

本文选题：超声电源　切入点：电流法　出处：《北京交通大学》2014年硕士论文

【摘要】：摘要：近年来,随着电子技术的飞速发展,超声技术得到了迅速的发展并被广泛应用。尤其是在超声加工方面,大功率超声技术的应用越来越广。不断提高的应用要求,反过来又促进了对超声电源研究的不断深入。实现频率自动跟踪和振幅恒定控制是超声电源的两个关键技术,各个研究者都在不断对其进行深入研究与改善。本文针对超声电源的频率自动跟踪、振幅恒定控制等关键技术,基于ARM Cortex-M3架构嵌入式微处理器STM32研制了一套智能化大功率超声电源。主要研究内容包括： (1)根据超声换能器的等效电路特性,分析了超声换能器的多峰值性和相位特性,提出了基于电流法和相位控制法相结合的频率自动跟踪方案,该方案既能在换能器开始工作前对换能器的谐振频率进行自动搜索,使得电源能自动适配具有不同谐振频率的换能器进行工作,还能对换能器在工作过程中发生的谐振频率漂移进行精确跟踪；同时基于换能器回路中电流有效值与换能器输出振幅的关系,设计了将换能器回路中电流有效值作为反馈信号来调节电源输出功率的方法,实现振幅恒定控制； (2)建立了超声电源主电路结构,并分别对整流、功率调节、逆变、匹配、反馈等进行了深入的分析。通过在整流环节使用Buck斩波器解决电源输出功率可调的问题；使用基于DDS技术的PWM波形发生器、基于RC延时电路的死区时间形成电路以及IR2110驱动芯片共同实现对全桥逆变电路的驱动,产生频率可高精度调节的交流信号来驱动换能器工作,该逆变部分的设计使控制器执行简单的步骤就能进行快速、高精度地频率自动跟踪；在反馈系统中根据反馈控制方案所改进的相位检测电路能极大简化控制器的软件设计,极大提升频率跟踪的速度； (3)根据超声电源的工作特点设计了控制系统软件程序,包括频率自动跟踪控制程序和振幅恒定控制程序,具体实现了控制思想。为了实现既快速又精确的控制,设计了变步长的控制策略。由于对各硬件部分的电路进行了优化设计,软件结构变得简单,使控制更加稳定； (4)基于理论设计完成了超声电源硬件的制作和软件的编写,进行了大量实验调试。并在实验过程中对不断发现的问题进行了理论研究与实践测试。实验结果表明,本文研制的大功率超声电源可使换能系统快速、准确地工作在谐振状态,振动过程稳定,所设计的软硬件系统较好实现了预期功能。
[Abstract]:Abstract: in recent years, with the rapid development of electronic technology, ultrasonic technology has been rapidly developed and widely used. On the other hand, the research on ultrasonic power supply has been further developed. The realization of frequency automatic tracking and amplitude constant control are two key technologies of ultrasonic power supply, which are studied and improved continuously by various researchers. Aiming at the key technologies of frequency automatic tracking and amplitude constant control of ultrasonic power supply, an intelligent high power ultrasonic power supply is developed based on embedded microprocessor STM32 based on ARM Cortex-M3 architecture. The main research contents are as follows:. 1) according to the equivalent circuit characteristics of ultrasonic transducer, the multi-peak and phase characteristics of ultrasonic transducer are analyzed, and a frequency automatic tracking scheme based on the combination of current method and phase control method is proposed. This scheme not only can automatically search the resonant frequency of the transducer before it starts working, but also can automatically adapt the power supply to the transducer with different resonant frequencies. The resonant frequency drift of the transducer can also be tracked accurately, and the relationship between the effective value of the current in the transducer loop and the output amplitude of the transducer can be obtained. The method of adjusting the output power of the power supply by using the effective value of the current in the transducer loop as the feedback signal is designed to realize the constant amplitude control. (2) the main circuit structure of ultrasonic power supply is established, and the rectifier, power regulation, inverter, matching, feedback and so on are analyzed in depth. The problem of adjustable output power of power supply is solved by using Buck chopper in rectifier. The PWM waveform generator based on DDS technology, the dead-time forming circuit based on RC delay circuit and the IR2110 driver chip are used to drive the full-bridge inverter circuit. The AC signal can be adjusted with high precision to drive the transducer. The design of the inverter part enables the controller to carry out fast and high-precision frequency automatic tracking by performing simple steps, and the improved phase detection circuit based on the feedback control scheme in the feedback system can greatly simplify the software design of the controller. Greatly improve the speed of frequency tracking; 3) according to the working characteristics of ultrasonic power supply, the software program of control system is designed, including frequency automatic tracking control program and amplitude constant control program. The control strategy of variable step size is designed. The software structure becomes simple and the control is more stable because of the optimized design of the circuits of each hardware part. 4) based on the theoretical design, the hardware and software of ultrasonic power supply are made, and a large number of experiments are carried out, and the problems found in the experiment are studied theoretically and tested in practice. The experimental results show that the high power ultrasonic power supply developed in this paper can make the energy transfer system work quickly and accurately in the resonant state and the vibration process is stable. The software and hardware system designed in this paper achieves the expected function well.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN86

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