基于DSP控制的功率因数校正技术的研究与应用

【作者】 邹修铁；

【导师】 陈特放；

【作者基本信息】 中南大学 ， 交通信息工程及控制， 2008， 硕士

【摘要】 随着电力电子装置的应用日益广泛,电网电流的谐波问题也日益严重,谐波污染给系统本身以及周围的电磁环境带来了一系列的危害。有源功率因数校正(active power factor correction,APFC)技术的优点是总谐波含量小,功率因数高。在此背景下,功率因数校正(PFC)技术成为电力电子技术的重要组成部分,并已经在越来越多的领域得到应用,成为电力电子技术领域一个新的研究热点。中大功率有源功率因数校正电路一般工作在连续导电模式,这样开关的电流应力比较小,但存在严重的二极管反向恢复问题。二极管反向恢复会引起较大的损耗和电磁干扰,限制了变换器功率密度的提高。论文阐明了传统功率因数校正的基本原理,并分析了各自的优点和不足。选择应用于单相功率因数校正领域的复合有源箝位电路,对复合有源箝位的工作过程进行了详细的论述。这种有源箝位电路能够有效地抑制二极管的反向恢复,并且利用谐振原理,实现所有开关的零电压开关,使开关器件的动态轨迹大为改善,开关损耗极小。此外,还消除了传统有源箝位电路中存在的寄生振荡的问题。用数字电路代替传统的模拟电路来实现对整个回路的控制,最终使得本文所设计的具有功率因数校正能力的整流器具有输入功率因数接近于1、低电流谐波的特性。针对复合有源箝位APFC系统中控制对象非线性和时变的特点,传统的PID控制难以达到令人满意的效果,本文利用模拟人体免疫系统反应的先进PID的控制算法作为控制算法,来提高系统抗负载扰动能力。通过计算机仿真和样机的调试证明了方案的可行性及其优点。最后,本文采用TI公司生产的TMS320LF2812型号的DSP作为主控芯片,完成了控制系统的硬件设计、软件设计,设计完成了一套1KW复合有源箝位的PFC数字化实验装置。并通过实验获得了较好的实验波形。实验结果证实了理论分析的正确性和控制方案的可行性,取得了预期的效果。更多还原

【Abstract】 With the extensive application of power electronics devices, the current harmonic problem becomes more and more terrible. The current harmonic pollution brings a series of harms to system and electromagnetism environment .Under this background , Power Factor Correction (PFC)Technology which is being used in many fields becomes important part and research hotspot of the power electronics technology.The PFC converters with middle or large out power usually work under continuous-conduction-mode(CCM), which have the advantage of low current stress on the switch. However, Which exists severe diode reverse recovery problem in the CCM PFC converters. It may lead to high switching loss and cause severe EMI problems.The characteristics of traditional analog PFC converters is analyzed, the principle and working mode is studied. Compound Active-Clamp topology is proposed in this paper. This topology can effectively suppress the diode reverse recovery, meanwhile create zero-voltage switching for all the switches. Under this circumstance, the dynamic switching loci of switches are proved greatly and the switching loss is reduced. The topology can also eliminate the unwanted voltage oscillation in the traditional active clamp topology. The theoretical analysis and design details of Compound Active-Clamp PFC circuit is proposed. The control-loop circuit is realized using digital control, and ultimately make the rectifier with PFC to increase power factor and reduce current harmonics.Traditional PID control is hard to use in the great nonlinearity and parameter variety of central conditioner. In order to ensure the system stability, the author brought forward a digital control circuit scheme and an Immune Feedback PID control algorithm. The computer simulation result and the prototype validated the feasibility and validity of the proposed theory.At last, A 1KW Compound Active-Clamp PFC test system is introduced based on TMS320LF2812. The author made a clear explication of control circuit and soft design. It is presented waveform of prototype to prove the feasibility of this research.更多还原