静电除尘用脉冲电源技术研究

发布时间：2018-04-05 15:12

本文选题：静电除尘　切入点：反电晕　出处：《南京航空航天大学》2017年硕士论文

【摘要】：静电除尘器被广泛应用于工业废气处理领域,在众多除尘方法中,其具有简单、高效及易于维护等诸多优点而广受业界好评。我国的静电工业静电除尘器于八九十年代由欧美等工业除尘开展较早的国家引入,其废气排放标准多为50~200mg/Nm3,早已不能满足当下出台的严格标准,静电除尘器的革新势在必行。相较于传统的工频电源及高频电源,脉冲除尘器利用高压脉冲短时间内使粉尘荷电,更容易清除细微粒特别是高比电阻细微粒粉尘,有效抑制反电晕,实现废气低排放;同时脉冲电源更节能,是国内外静电除尘领域的研究热点。首先,本文针对静电除尘器的负载特性和除尘效率影响因素做研究,通过对空气放电特性、非稳态静电除尘理论的研究,得到最优供电电压、电晕电流密度的数学表达式;通过对粉尘比电阻、高比电阻粉尘收集过程的研究解释了直流电源的局限性及脉冲电源的优势;通过研究直流叠加脉冲电场中粉尘的运动,优化了多依奇除尘效率公式;为脉冲电源的设计提供理论依据。其次,本文针对直流叠加脉冲电源高压侧电源提出了一种新直流叠加脉冲电源的设计方法。通过建立其数学模型,采用拉普拉斯变换对数学模型进行解析,分别对正常工作、闪络及火花状态进行模态分析,得到正常与极端情况电压与电流的数量关系;通过对正常工作模态的谐振状态和震荡状态的数学解析、标幺化及参数影响特性分析,设计电路中的重要参数,形成直流叠加脉冲电源设计的理论基础。再次,本文针对直流叠加脉冲电源的供电电源进行研究。选用全桥LCC拓扑作为研究对象,由于高频高压变压器存在较大寄生参数,且寄生参数的大小与变压器参数及绕制工艺存在联系;因此,采用LCC谐振利用高频高压变压器的寄生参数,使开关器件工作在软开关状态。深入研究其DCM两种模式,对比分析平均输出电流、谐振电流峰值、调压特性、软开关特性等,得到电源关键参数的设计依据及DCM-1模式更适用于高压静电除尘场合的结论。最后,本文分别搭建了小型直流叠加脉冲静电除尘系统和LCC供电电源进行系统实验验证。对直流叠加脉冲电源及LCC供电电源分别通过系统参数设计,软件仿真、和硬件实验验证等环节,验证直流叠加脉冲电源及LCC供电电源系统理论分析的正确性及系统可行性,实验波形与仿真及设计预期基本相符,标志着理论分析的正确性和设计方法的可行性。本文工作为应用于静电除尘领域的直流叠加脉冲静电除尘器提供了理论分析与设计方法,对于直流叠加脉冲静电除尘电源系统在除尘器领域中的应用具有一定的意义和参考价值。
[Abstract]:Electrostatic precipitator (ESP) is widely used in the field of industrial waste gas treatment. In many dust removal methods, it has many advantages, such as simple, efficient and easy to maintain.The electrostatic precipitator in our country was introduced by Europe and America in 1980s and 1990s, and its exhaust gas emission standard is mostly 50 ~ 200mg / Nm ~ 3, which can not meet the strict standard, so the innovation of electrostatic precipitator is imperative.Compared with the traditional power supply and high frequency power supply, the pulse dust collector can charge the dust in a short period of time by using the high voltage pulse, it is easier to remove fine particles, especially the fine particle dust with high specific resistance, effectively restrain the corona back, and realize the low emission of waste gas.At the same time, pulse power supply is more energy-saving, is the domestic and foreign electrostatic dust field research hot spot.Firstly, this paper studies the load characteristics of electrostatic precipitator and the influencing factors of dust removal efficiency. The mathematical expressions of optimal power supply voltage and corona current density are obtained by studying the characteristics of air discharge and the theory of unsteady electrostatic dust collection.The limitation of DC power supply and the advantages of pulse power supply are explained through the research of dust specific resistance and high specific resistance dust collection process, and the formula of dust removal efficiency is optimized by studying the movement of dust in DC superposition pulse electric field.It provides theoretical basis for the design of pulse power supply.Secondly, this paper presents a new design method of DC superposition pulse power supply for high voltage side power supply.The mathematical model is established and the Laplace transform is used to analyze the mathematical model. The modal analysis of normal operation flashover and spark state is carried out respectively and the quantitative relationship between voltage and current in normal and extreme cases is obtained.Through the mathematical analysis of the resonance state and oscillation state of the normal working mode, the analysis of the standardization and the influence characteristics of the parameters, and the design of important parameters in the circuit, the theoretical basis of the design of DC superposition pulse power supply is formed.Thirdly, this paper studies the power supply of DC superposition pulse power supply.The full-bridge LCC topology is chosen as the research object. Because there are large parasitic parameters in high-frequency and high-voltage transformers, and the size of parasitic parameters is related to transformer parameters and winding process, therefore,Using LCC resonance, the parasitic parameters of high frequency and high voltage transformer are used to make the switching device work in soft switching state.In this paper, two DCM modes are studied, and the average output current, resonant current peak value, voltage regulation characteristic and soft switching characteristic are compared and analyzed. The design basis of the key parameters of the power supply and the conclusion that DCM-1 mode is more suitable for electrostatic dust removal at high voltage are obtained.Finally, a small DC superposition pulse electrostatic dust removal system and a LCC power supply are built to verify the system.The correctness and feasibility of theoretical analysis of DC superposition pulse power supply and LCC power supply system are verified by system parameter design, software simulation, and hardware experiment verification for DC superposition pulse power supply and LCC power supply.The experimental waveform is basically consistent with the simulation and design expectation, which indicates the correctness of theoretical analysis and the feasibility of design method.This paper provides a theoretical analysis and design method for DC superimposed pulse electrostatic precipitator used in electrostatic dust collection field.It has certain significance and reference value for the application of DC superposition pulse electrostatic dust collection power system in the field of dust collector.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN86

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