【作者】 马坤；

【导师】 张庆范；

【作者基本信息】 山东大学 ， 控制理论与控制工程， 2008， 硕士

【摘要】 超声技术出现在二十世纪初期,近一个世纪的发展表明,超声技术是声学发展中最为活跃的一个部分,如今它已经渗透到国防建设、国民经济、人民生活和科学技术等各个领域。其中超声波清洗技术也得到了广泛的发展,相比其他多种的清洗方式,超声波清洗显示出了巨大的优越性。超声波清洗机的高效率和高清洁度,得益于其声波在介质中传播时产生的穿透性和空化冲击波,所以很容易将带有复杂外形,内腔和细孔的零部件清洗干净。超声清洗的物理机制主要是超声空化,所以要达到良好的效果必须选择合适的声学参数和清洗剂的物理化学性质。声强愈高,空化愈强烈,但声强达到一定值后,空化趋于饱和。超声波清洗机主要由超声波发生器和超声波换能器组成,本文重点介绍超声波发生器。本文涉及以下几方面的内容:1、主回路的研究:包括逆变主电路、开关管的保护、功率管驱动和高频变压器的设计,即输入电路(包括输入保护电路、整流滤波电路)、半桥逆变电路(超声频发生电路)和匹配电路(电感匹配)。主电路设计在满足产生超声频信号和最佳匹配的要求下,又可以使在电网电压过大或者过小输入时保护发生器。半桥逆变驱动电路的设计本文采用的是IR公司的集成半桥驱动器IR21844。用这种方法可以避免设计驱动变压器,简化设计步骤,同时可以减少元件,节省成本。2、换能器电端匹配网络研究:本文介绍了几种常见的匹配网络,并且根据实际要求选择电感匹配网络。在设计匹配电感参数时,应用阻抗分析仪精确测量了清洗槽(带有换能器)中有负载(清洗液)时的等效电路的电参数,并根据数学推导出来的匹配电感计算公式求出匹配电感的感值。3、实现自动频率跟踪的控制电路:本文采用了数字锁相环的方法,利用集成数字锁相环CD4046和较少的独立元件构成锁相电路,从而提高了自动频率跟踪的可靠性。4、数字PWM信号发生器研究设计:采用直接数字频率合成技术(DDS技术)作为信号发生器,将DDS技术应用于信号源中可以大大提高信号源的分辨率,有效的降低成本、缩小体积。更多还原

【Abstract】 Ultrasound technology appeared in the early twentieth century. Nearly a century’s development has shown that ultrasound technology is the most active part in the acoustic development. Now it has penetrated into the building of national defense, national economy, people’s livelihood, and science and technology fields. Of all these, ultrasonic cleaning technology has been extensively developed. Compared with a variety of other cleaning measures, ultrasonic cleaning has shown significant advantages. High efficiency and high cleanliness of ultrasonic cleaning machines derive from its penetrability and shock wave of air when the sound is communicated in the medium. So it is easy to clean those parts with complex shapes, inner cavity and stomas. The physical mechanism of Ultrasonic cleaning is ultrasound shock wave of air. In order to achieve good results, acoustic parameters and the physical and chemical properties of appropriate cleaning agentia must be selected. The higher the sound intensity is, the stronger shock wave of air is. But when the sound intensity reached a certain value, shock wave of air intends to saturation. Ultrasonic cleaning machines is mainly made up of ultrasonic generator and ultrasonic transducer. The paper focuses on ultrasonic Generator.This paper covers the following several aspects:1 .Main circuit research, including main inverter circuits, the protection of switch valves, the driver of power tubes and design of high frequency power transformers, namely, input circuits (including input protection circuits, rectifier filter circuits), the half-bridge inverter circuits (ultra - Audio circuit) and matching circuit (inductance match). On the one hand, the main circuit design can meet the demand of producing ultrasound frequency signals and the best match. On the other hand, it can protect the generators when a too small or too large power grid voltage is input. The design of half-bridge inverter drive circuits used in this paper is integrated half-bridge drive IR21844 from IR Corporation. In this way We can avoid designing driven transformers, simplify the designing steps, and can reduce components, saving cost.2.the research of transducer-matching network: The paper introduces a couple of common matching networks and selects inductance match networks according to practical requirements. During the course of designing matched inductance parameters, we accurately measures the electrical parameters of the equivalent circuits in the tank with loads through an impedance analyzer and work out the value of matched inductance using mathematical formula.3. control circuits of automatic frequency tracking. The paper takes the method of PLL. The PLL is made up of integrated digital PLL CD4046 and less independent components. Thus, the reliability of automatic frequency tracking is improved.4.design of digital PWM signal generator. The signal generator is using direct digital synthesis technology (DDS technology). It can greatly improve the resolution, effectively reduce costs and reduce the volume.更多还原