双馈变流器检测系统故障诊断与容错控制研究

发布时间：2018-06-29 00:23

本文选题：双馈风电变流器 + 检测系统　；参考：《哈尔滨工业大学》2014年硕士论文

【摘要】：在可再生能源利用技术中，风力发电技术是一种具有发展前景且相当成熟的技术。经过多年快速发展，全球风电行业进入平稳增长阶段，而海上风电场规模不断扩大。随着我国风电并网规模扩大及海上风电场的发展，对风力发电技术的可靠性有了更高的要求。因此本文针对应用最广泛的双馈风电机组从提高其安全性和可靠性方面入手，对双馈电机定转子电流检测系统故障诊断、转速检测系统故障诊断及故障后系统容错控制三方面进行研究。双馈电机控制系统设计一般在连续时间域内进行，而在实际应用中都在离散时间域实现。本文根据双馈电机T型等效电路推导了其数学模型，并据此推导出以定转子电流为状态变量的连续时间状态方程并将其离散化得到离散时间状态方程，对离散化误差进行了分析。从双馈电机极点分布角度并结合电流控制器对系统稳定性进行分析，并分析了系统的可观性，为电流观测器的设计提供理论支持。电流检测系统的可靠工作对双馈变流器稳定运行至关重要。本文建立了双馈电机定转子电流降阶观测器，并提出基于电流预测的电流检测系统故障诊断方案。通过极点配置使电流降阶观测器快速稳定地跟踪实际电流，实现电流信号的冗余并使用观测值实现故障后系统重构；基于电流预测的故障诊断方案能够快速诊断出故障信号，，理论上最少只需要一个控制周期，且故障诊断方案不受功率波动、电网故障等的影响。研究结果表明，通过故障自诊断及容错控制，使功率变流器在部分检测信号故障情况下保持并网可控运行，可以有效的提高系统的可靠性。转速信号检测系统的可靠工作同样重要。在转子电流降阶观测器的基础上利用模型参考自适应理论，建立了转速自适应观测器，能够准确快速观测出电机转速。同时设计一种速度检测系统故障诊断方案，能够快速诊断出转速故障信号，使用转速及转子位置角观测值实现容错控制。研究表明所提方案能够实现转速检测系统故障后系统可控运行，对提高系统可靠性有重要意义。由于电流及转速观测器运算量较大，设计并制作了基于TMS320F28335的双馈风电变流器控制器，完成双馈风电模拟机组的并网运行并对所提电流和转速观测器及故障诊断方案进行实验验证。
[Abstract]:In renewable energy utilization technology, wind power generation technology is a promising and quite mature technology. After years of rapid development, the global wind power industry has entered a stable growth stage, and the scale of offshore wind farms is expanding. With the expansion of wind power grid in China and the development of offshore wind farm, the reliability of wind power generation technology has higher requirements. Therefore, this paper starts with improving the safety and reliability of doubly-fed wind turbine, and diagnoses the fault of its stator and rotor current detection system. The fault diagnosis of rotational speed detection system and fault-tolerant control of post-fault system are studied. The design of doubly-fed motor control system is usually carried out in the continuous time domain, but it is realized in the discrete time domain in the practical application. In this paper, the mathematical model of the T-type equivalent circuit of a doubly-fed machine is derived, and the continuous time state equation with the stator and rotor current as the state variable is derived and discretized to obtain the discrete time state equation. The discretization error is analyzed. The stability of the system is analyzed from the angle of pole distribution and current controller, and the observability of the system is analyzed, which provides theoretical support for the design of the current observer. The reliable operation of the current detection system is very important to the stable operation of the doubly-fed converter. In this paper, a reduced order observer for the stator and rotor current of a doubly-fed machine is established, and a fault diagnosis scheme for the current detection system based on current prediction is proposed. The current reduced-order observer can track the actual current quickly and stably by pole assignment, realize the redundancy of current signal and reconstruct the system after fault by using the observation value, and the fault diagnosis scheme based on current prediction can quickly diagnose the fault signal. In theory, at least one control period is required, and the fault diagnosis scheme is not affected by power fluctuation and power network faults. The research results show that through fault self-diagnosis and fault-tolerant control, the power converter can be controlled and connected to the grid under the condition of partial fault detection signal, and the reliability of the system can be improved effectively. The reliable operation of the speed signal detection system is equally important. Based on the rotor current reduced-order observer, a rotational speed adaptive observer is established by using the model reference adaptive theory, which can accurately and quickly observe the motor speed. At the same time, a fault diagnosis scheme of speed detection system is designed, which can quickly diagnose the fault signal of speed, and realize fault-tolerant control using the observation value of rotational speed and rotor position angle. The research shows that the proposed scheme can realize the controllable operation of the system after the system failure, and it is of great significance to improve the reliability of the system. A doubly-fed wind converter controller based on TMS320F28335 is designed and fabricated because of the large computation of current and speed observer. The grid-connected operation of doubly-fed wind power simulator is completed, and the proposed current and speed observer and fault diagnosis scheme are verified experimentally.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM46

【共引文献】