【作者】 唐雄民；

【导师】 彭永进；

【作者基本信息】 湖南大学 ， 控制理论与控制工程， 2007， 博士

【摘要】 臭氧(化学表达式为:O3)。常温常压下是一种不稳定的淡蓝色气体,很容易被分解为氧气,不产生二次污染,属于一种无公害、无污染、无残留的氧化与消毒剂。因此,臭氧被大量应用于有机合成、无机化工、冶金、造纸、印染、食品保鲜和医疗器具及餐具消毒等领域,涉及到人们生活的各个方面,并被广泛应用于自来水净化和工业、生活污废水的处理。产生臭氧的方法主要有紫外线照射法、电解法、放射化学法和介质阻挡放电法,在这些方法中介质阻挡放电法(DBD)具有能耗相对较低、单机臭氧产量大,气源可为干燥空气、氧气或含氧浓度较高的富氧气体、便于工业现场生产等优点,因此工业上合成臭氧大多采用该法。目前国内大多数臭氧设备商生产的大功率臭氧发生器大多采用将逆变电路输出方波经升压变压器直接施加于臭氧发生器上,并且电路采用开环控制,整个电源系统存在开关管损耗和开关应力大,开关管和与开关管并联的吸收回路发热严重、整个发生器系统效率低、电路输出功率难以进一步提高的问题,严重的限制了臭氧发生器系统在国内的推广。针对这些问题,本文采用基于全桥串联负载谐振的供电电源来解决原有电源系统存在的问题,并从电源系统主要电气量的电气调节特性、软开关实现技术和多功能控制回路的实现等三个方面,对大功率臭氧发生器供电电源进行了研究和探讨,本文的主要研究工作包括以下几个部分:(1)针对目前臭氧供电电源的分析和设计方法主要依赖经验而不能精确地反映电路工作的实际过程,本文从DBD电路的原始等效电路出发,用时域分析的方法对PFR容性控制、PFR感性控制、PSC感性控制下的DBD电路进行了详细地理论推导和分析,得出了DBD电路的工作频率、逆变电路输出电流峰值、发生器承受的峰值电压和电路的放电功率的显性表达式及对应的调节特性,并采用实验的方法验证了推导的正确性。(2)针对目前还没有相关文献对不同控制方式下的全桥串联负载谐振式DBD电源的性能展开对比分析和研究,为填补这一空白,本文以电路中主要电气量的调节特性为基础,对三种控制方式下电路性能进行对比分析,得到了中、低频下的DBD电源系统适合采用容性控制,而高频下的DBD电源系统适合采用PSC感性控制的结论。这一工作能使臭氧电源设计者能根据实际需要选择适合的控制方式。(3)为降低时域分析方法的复杂和烦琐,本文利用串联谐振电路工作时电流接近正弦波这一特性,提出了串联负载谐振式DBD电路的基波分析方法,推导了DBD电源中主要电气量的表达式。理论计算结果、仿真和实验结果表明,三者的相对误差小于8%。与时域分析法比较,采用基波分析方法计算得到的结果虽然较时域分析法计算得到的结果稍差,但具有简便和实用的特点,有比较现实的工程意义。另外在这一部分,在基波分析方法的基础上提出了串联谐振式DBD电源的基波设计法,它是一种简单和实用的设计方法,实践结果表明本文提出的基波等效设计方法具有快捷、方便和精度相对较高的特点,是一种简捷实用的配套电源设计方法。(4)在现有全桥串联负载谐振式电源的频率跟踪环节的进行了归纳和分析的基础上,得到了PFR容性、PFR感性和PSC感性控制的频率跟踪的通用的实现方法,并以此基础提出了一种能提高DBD电路的放电效率的新型三环调节器,该调节器由功率滞环控制器、发生管峰值电压调节器和相位控制调节器组成,仿真结果表明,这种新型控制系统优于现有的广泛使用的PDM等控制方案,它不仅能满足DBD电源的控制系统的基本要求:在保证DBD电路工作在最佳放电电压的前提下连续地调节电源的输出功率,而且具有更强的抗扰动能力,彻底解决了发生器过压的问题。(5)从控制回路工作的可靠性、良好的保密性和调试的便利性出发,采用了以CPLD/FPGA为核心控制芯片的控制方案,并根据电力电子系统在本质上可以视为离散系统这一特征,提出了电力电子电路控制系统的有限状态机建模方法。在这两者的基础上实现了采用一套硬件方法实现了电路的PFR感性、PFR容性和PSC感性控制。(6)对在串联谐振DBD电源中实现ZVS(ZeroVoltageSwitching)的方法进行了探讨。在研究中放弃了认为开关管切换时电流恒定这一假设,从功率Mosfet管实际开关过程中电流变化规律出发,提出了一种新的等效电路,并依此为工具,详细地研究了串联谐振供电DBD电源的ZVS实现方法。(7)利用本文提出的分析方法和设计公式,作者试制了一台1kgO3/h的串联负载谐振式臭氧发生器供电电源,实验表明电源系统能满足设计要求,已在番禺某厂投入了运行,它能长时间可靠地工作,并得到了用户的认可。更多还原

【Abstract】 Ozone is one of the strongest oxidizing and bleaching agents without residues that could be harmful to the environment. For this reason, ozone has been used for a variety of applications, such as bleaching, deodorization and disinfection of water and industrial waste water. Ozone has being played more and more important role in the development of the nature environment .However, ozone is unstable in normal temperature and readily turns into oxygen, which leads to that ozone is hard to be stored and transport. So it must be generated at point of use. Now, there are a lot of methods to generate ozone, such as ultraviolet radiation irradiation method, electro-analysis method, radiation method, DBD (Dielectric Barrier Discharge) method and so on. In these methods, DBD method has a lot of merits, such as low energy dissipation, higher yield of single equipment, being easy to generate ozone in working field. So DBD method is widely adopted in industrial ozone produce.At present, the square wave formed by serial inverter is directly applied to ozone generator and the control system is open loop control in most ozone equipment manufacturer, so there exist low working frequency, big switch loss, big switch stress and difficultly increasing the output discharge power in the power supply for ozone generator.Aim at these questions, a full bridge serial load resonant DBD type power supply of ozone generator has been studied, including the formulas describing the main electric characteristics vs. system parameters are deduced, the MOSFET soft switching technique of inverter is developed and the multifunctional control system is composed. These researches and studies have important roles in both theories and applications.The main achievements obtained by this dissertation are:(1) At present, the design of power supply for ozone generator mostly depends on the experience and approximate equivalent impedance gotten from the working current and working voltage analysis. So these design methods can’t describe the working process of DBD circuit. To solver the question, a method of modes analysis is adopted by combining the on-off conditions of the power switch and the states of discharge or not discharge in DBD circuit.(2)There are not relevant documents and references about the performance analysis of DBD type ozone generator powered by serial load resonant inverter. In order to solver the questions, the expresses and regulating characteristics of main electric parameters are deduced under the PFR(Power Factor Regulation) capacitive load control, the PFR inductive load control and PSC(Phase Shifting Control) inductive load control . These researches are validated by experiments. The conclusions can make the designer to choose reasonable control scheme according to actual needs.(3) In order to avoid the analysis difficulties of DBD circuit in time domain method, a new fundamental wave analysis method of DBD circuit is presented since the current of inverter is closed to sinusoidal wave. Based on the fundamental wave analysis method, the formulas describing the main electric characteristics vs. system parameters are achieved. The errors between the calculation results, the simulation results and the experiment results are less than 8%. Compared with the time domain method, the fundamental analysis is more concise, and has engineering value. And a kind of power supply design method of DBD circuit is presented based on the fundamental wave analysis, the design method is a high performance design method validated by experiments.(4) After synthesis of the existing methods, a general frequency track method of PFR capacitive control, PFR inductive control and PSC inductive control is achieved Based on the general frequency track realizing ways, a new control system is present, which consist of power lag relay controller, peak voltage of DBD circuit regulator and inverter power factor angle regulator. Simulation results show that the new control system not only can regulate the discharge power in the optimum discharge voltage but also solver the over-voltage of DBD circuit, so the performance of the new control system is better than the other control system, such as PDM (Pulse Density Modulation) etc al.(5) For the reason of secrecy and convenient to debug, a new control system based on CPLD/FPGA chip is built. Since a power electronic circuit is essentially a discrete event system, a model method of its control system is presented base on the FSM (Finite State Machine) theory. With this control model, the PFR capacitive control, PFR inductive control and PSC inductive control can be realized in a same set of hardware. Experiments prove that the control model can be applied in most power electronic circuits.(6) The ZVS (Zero Voltage Switching) techniques of ozone generating inverter using MOSFET as the power switches are studied, and a new kind of equivalent circuit describing the turn-off transients of the MOSFET is presented according to the actual process of MOSFET. Based on this equivalent circuit, the soft-switching characteristics are studied and a design method is put forwards. The conclusions are proved by simulations.(7)By the analysis and design method in the paper, a 1kgO3/h ozone generator powered by serial load resonant inverter is built. The experiments results show the power supply can satisfied the design requirements. The ozone generator has been running in a factory located in PanYu, Guangdong Province. It works reliably, and obtains the user’praise.更多还原