开关电源PFC校正数字控制算法研究

发布时间：2018-05-04 08:13

本文选题：开关电源 + 功率因数校正　；参考：《昆明理工大学》2017年硕士论文

【摘要】：在电力电子发展史中,开关电源作为一种损耗小、效率高、电路简洁、可靠性高的电源装置,已被广泛应用于各类工业生产、电子设备及日常生活等领域。但其与电网相连的整流装置结构特殊,导致输入电流中含有大量谐波污染电网,十分不利于“绿色化”电网的构建,因此为开关电源设计一个功率因数校正装置势在必行,从而避免谐波污染所带来的一系列问题。在进入二十一世纪之前功率因数校正技术都是由模拟元器件或者是集成芯片来搭建控制电路,但这种方式很容易受到器件老化、温度以及外界干扰的影响,校正系统稳定性不高。随着微处理器、数字信号处理器及现场可编程门阵列控制器件的普及,既可以用数字控制方式来实现普通的模拟控制方案,又可将现代控制理论应用于功率因数校正。其高速的采样频率和快速的信号处理速度使得PFC数字控制成为研究趋势。本文从功率因数的定义入手,在假设输入电压无谐波的前提下,从原理上分析出与其至关重要的两个因素:谐波因子和相位因子,从而获得提高功率因数的两种途径:一是减少输入电流与输入电压之间的相位差提高cosφ值;二是使得输入电流波形很好地跟随正弦输入电压波形,减少输入电流的THD。选择Boost电路为APFC变换器主拓扑,在CCM工作模式下采用三端开关器件建模法对电路进行稳态及小信号扰动分析,并建立各扰动参量之间的传递函数。文中对现有的功率因数校正技术做一简单总结对比,选用平均电流双环数字控制方式来实现PFC,根据电路建模获得的各传递函数分别设计出电流内环、电压外环以及电压前馈部分,并在MATLAB上搭建仿真模型,验证此控制策略的效果。为了提高系统校正精度,利用Delta算子对高速采样获得的离散信号连续化,本文在以上基础上又提出了一种基于滑模变PI数字控制器的APFC,并在MATLAB平台上建立仿真模型验证了此算法能有效提高功率因数,并且精度高,抗干扰能力强,具有较强的鲁棒性,效果明显优于平均电流双环数字控制方式。
[Abstract]:In the history of power electronics, switching power supply, as a power supply device with low loss, high efficiency, simple circuit and high reliability, has been widely used in industrial production, electronic equipment and daily life. But the special structure of the rectifier connected with the power grid leads to a large amount of harmonic pollution in the input current, which is very unfavorable to the construction of the "green" power grid, so it is imperative to design a power factor correction device for the switching power supply. In order to avoid harmonic pollution caused by a series of problems. Before entering the 21 century, power factor correction (PFC) technology was constructed by analog components or integrated chips, but this method is vulnerable to the aging of devices, temperature and external interference. The stability of the correction system is not high. With the popularity of microprocessors, digital signal processors and field programmable gate array control devices, the common analog control scheme can be realized by digital control mode, and the modern control theory can be applied to power factor correction. Its high sampling frequency and fast signal processing speed make PFC digital control a research trend. Based on the definition of power factor and assuming that the input voltage has no harmonics, this paper analyzes two important factors in principle: harmonic factor and phase factor. Two ways to improve the power factor are obtained: one is to reduce the phase difference between input current and input voltage to increase the cos 蠁 value, the other is to make the input current waveform follow the sinusoidal input voltage waveform well and reduce the THD of input current. The Boost circuit is chosen as the main topology of the APFC converter. The three-terminal switching device modeling method is used to analyze the steady state and small signal disturbance of the circuit in CCM mode, and the transfer function between the disturbance parameters is established. In this paper, the existing power factor correction technology is summarized and compared, the average current double loop digital control method is used to realize PFC, and the inner current loop is designed according to each transfer function of circuit modeling. The voltage outer loop and the voltage feedforward part are simulated on MATLAB to verify the effectiveness of the control strategy. In order to improve the correction accuracy of the system, the discrete signals obtained by high-speed sampling are continuous by using Delta operator. In this paper, a sliding mode variable Pi digital controller is proposed, and the simulation model based on MATLAB platform is established to verify that the algorithm can effectively improve the power factor, and has high precision, strong anti-jamming ability and strong robustness. The effect is obviously better than the average current double loop digital control mode.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN86

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