四桥臂有源电力滤波器IGBT开路故障诊断与容错控制研究

发布时间：2018-04-24 19:06

本文选题：四桥臂有源电力滤波器 + 开路故障诊断　；参考：《中国矿业大学》2017年硕士论文

【摘要】：随着各种电力电子设备在生产生活各领域的广泛使用,三相四线制配电网中谐波电流与三相不平衡等电能质量问题日渐严重,有源电力滤波器(APF)已成为配电网中谐波治理的重要手段。APF主电路中IGBT发生故障后会影响谐波治理效果,严重时还会对APF设备与配电网带来次生危害。为提高APF设备的可靠性与安全性,本文以两电平四桥臂APF为研究对象,介绍其谐波检测与电流跟踪控制方法,并着重对其IGBT开路故障诊断方法与故障后相应的容错控制策略进行研究。首先,在abc坐标系与αβγ坐标系下建立四桥臂APF的数学模型,介绍了基于准VPI控制器的电流跟踪策略,为后文中故障诊断方法的研究提供基础。接下来,给出一种基于正弦幅值积分器(SAI)的改进dq谐波检测方法。该方法采用基于SAI的正序分量提取环节与多通道解耦滤波的结构增强了dq检测方法对畸变电网条件的适应能力,同时引入滑窗积分滤波器滤除电网电压中直流分量,并引入了反馈归一化锁频环消除频率波动的影响。仿真验证了此改进dq检测方法的有效性。其次,给出一种基于参考电压的IGBT开路故障诊断方法。找出不同位置IGBT开路后参考电压在各轴直流分量的变化规律,以参考电压在各轴直流分量的变化率为诊断变量,将中性线补偿电流作为N相桥臂的辅助诊断变量,实现了对四个桥臂所有IGBT开路故障的诊断与定位,且无需外加传感器。通过仿真模拟多种典型开路故障,验证了该算法适用于单管与多管开路故障的诊断,并且不受负载突变的影响。再次,给出变流器输出电压与参考电压相结合的IGBT开路故障诊断方法。该方法通过变流器输出电压与参考电压之间的符号关系对故障IGBT进行诊断与定位,并同样使用中性线补偿电流辅助N相桥臂的诊断。此方法通过APF的离散数学模型根据电流采样值对变流器输出电压进行计算,无需外加传感器,并且无需设置诊断阈值,具有更高的可靠性。在多种典型故障下的仿真分析,验证了算法对于单管与多管故障的有效性以及对不同工况的适应性。最后,设计了针对两电平四桥臂APF的容错拓扑及其调制与控制方法。采用被动隔离技术与开关冗余结构实现了单相桥臂故障的隔离与容错。给出适用于不对称容错拓扑的3D-SVPWM调制算法,研究了容错拓扑直流侧稳压与均压控制的方法,并对控制器参数进行设计。仿真证明APF运行于不对称容错拓扑下时仍然有较好的谐波治理效果,直流侧稳压与均压控制器能够保持直流侧电压的总体稳定与上下电容电压的平衡。
[Abstract]:With the wide use of various power electronic devices in various fields of production and life, the power quality problems such as harmonic current and three-phase imbalance in three-phase four-wire distribution network are becoming more and more serious. APF (active Power filter) has become an important means of harmonic control in distribution network. The failure of IGBT in the main circuit of APF will affect the effect of harmonic treatment and bring secondary harm to APF equipment and distribution network. In order to improve the reliability and safety of APF equipment, this paper takes two-level four-arm APF as the research object, and introduces its harmonic detection and current tracking control method. The open circuit fault diagnosis method of IGBT and the corresponding fault-tolerant control strategy after fault are studied. Firstly, the mathematical model of four-arm APF is established in abc coordinate system and 伪尾纬 coordinate system, and the current tracking strategy based on quasi VPI controller is introduced, which provides the basis for the research of fault diagnosis method in the future. Then, an improved dq harmonic detection method based on sinusoidal integrator is presented. In this method, the structure of positive sequence component extraction based on SAI and multi-channel decoupling filter is used to enhance the adaptability of dq detection method to distorted power network conditions, and the sliding window integral filter is introduced to filter DC component in power grid voltage. The feedback normalized frequency locking loop is introduced to eliminate the influence of frequency fluctuation. Simulation results show the effectiveness of the improved dq detection method. Secondly, an open circuit fault diagnosis method for IGBT based on reference voltage is presented. To find out the variation rule of the reference voltage in the DC component of each axis after the IGBT open circuit at different positions, taking the change rate of the reference voltage in the DC component of each axis as the diagnostic variable, and taking the compensation current of the neutral line as the auxiliary diagnostic variable of the N-phase bridge arm. The diagnosis and location of all open circuit faults of IGBT with four arms are realized, and no additional sensors are needed. By simulating several typical open circuit faults, it is proved that the algorithm is suitable for the diagnosis of single and multiple open circuit faults, and is not affected by the sudden change of load. Thirdly, the open circuit fault diagnosis method of IGBT combined with output voltage and reference voltage is presented. The fault IGBT is diagnosed and located by the symbolic relation between the output voltage and the reference voltage of the converter, and the neutral line compensation current is also used to assist the diagnosis of the N-phase bridge arm. This method is based on the discrete mathematical model of APF to calculate the output voltage of the converter according to the current sampling value. The method does not require additional sensors and requires no setting of diagnostic threshold, so it has higher reliability. The simulation results show that the algorithm is effective for single-tube and multi-tube faults and adaptive to different working conditions. Finally, the fault-tolerant topology and modulation and control methods for two-level four-arm APF are designed. The passive isolation technique and the switch redundancy structure are used to realize the fault isolation and fault tolerance of the single phase bridge arm. The 3D-SVPWM modulation algorithm suitable for asymmetric fault-tolerant topology is presented. The methods of voltage stabilization and voltage sharing control on DC side of fault-tolerant topology are studied and the controller parameters are designed. Simulation results show that APF still has a good harmonic control effect when it runs under asymmetric fault-tolerant topology. The DC side voltage stabilizer and voltage sharing controller can maintain the overall stability of DC side voltage and the balance of upper and lower capacitance voltage.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM761

【参考文献】