高可用度长寿命并联型风电变流器研究

发布时间：2018-05-06 03:27

本文选题：并联型风电变流器 + 可靠性　；参考：《上海交通大学》2014年博士论文

【摘要】：随着环境污染和能源短缺日益严重，风能作为常见的可再生洁净能源，在近年来得到了充分的开发和广泛的应用，风力发电技术也在世界范围内得到了巨大的发展。随着陆上资源的开发，可再开发的风能资源有限，与陆上风电场相比，海上风电场具有风资源持续稳定、风速高、发电量大、不占用土地资源、环境噪音和视觉影响小等特点，因此，海上风电已成为未来风电发展的重要选择。然而海上风电机组容量大、工作环境恶劣、维修困难等特点，在可靠性方面对机组提出了更高的要求，变流器是风电机组的关键部件，设计高可靠性的变流器至关重要。由于鼠笼式感应电机的高可靠性、强鲁棒性，同时全功率变流器解耦电机与电网，在一定程度上解耦机械传动部分和电网的交互，有利于提高机械部分的可靠性。本文将立足于鼠笼感应发电机（Squirrel Cage InductionGenerator，SCIG）的全功率风力发电机组展开研究。基于该机组类型，研究面向高可靠性的风电变流器拓扑、调制以及控制策略。本文的主要工作： 1)基于半导体器件物理失效机理的可靠性评估方法对风力发电变流器的可靠性进行评估。量化分析风能的波动性和间歇性对变流器的故障率以及寿命的影响，为提升风电变流器设计的可靠性提供理论依据。 2)基于高可用度的设计，提出具有冗余功能的系统级并联风电变流器拓扑结构，并对该拓扑结构进行可靠性评估，并提出经济最优化的N+X并联型风电变流器冗余设计方法。针对并联型这种复杂大规模电力电子装置有提出了高可靠的分布式控制系统的设计方法。同时研究并联型风电变流器的运行、控制与保护控制策略，实现变流器故障重构后风电机组限功率再运行。 3)从降低功率器件平均结温可以延长变流器寿命的可靠性机理出发，提出基于DPWM的交错并联调制方式，最大化地减小功率开关损耗，，从而降低其平均结温，提高变流器的可靠性。本文又分析了采用基于DPWM的交错并联方式而引起的谐波偏大以及零序环流问题，针对新出现的问题提出优化调制与控制策略，从而在保证风电变流器性能的情况下，大幅提高变流器的可靠运行能力。 4)提出了并联型变流器中子系统间无功环流和正交环流的热控制技术，研究了风电变流器两种基于热控制的状态控制方法。首先从平滑功率器件结温波动可以延长变流器寿命的可靠性机理出发，以平滑结温波动为目标，提出了基于环流热控制技术实现结温波动平滑控制。再次针对由于风能的突降将造成柜内凝露现象，通过减缓结温下降速度为目标的基于环流热控制技术，可以防止凝露现象，从而降低变流器的故障率，亦提升了变流器的可靠性。本文对上述提出的控制策略及调制方法进行了理论分析，数学建模以及仿真实验验证。
[Abstract]:With the increasing environmental pollution and energy shortage wind energy as a common renewable clean energy in recent years has been fully developed and widely used wind power generation technology has also been a huge development in the world. With the development of onshore resources, wind energy resources that can be redeveloped are limited. Compared with onshore wind farms, offshore wind farms have the characteristics of sustained stability of wind resources, high wind speed, large electricity generation, non-occupation of land resources, low environmental noise and visual impact, etc. Therefore, offshore wind power has become an important choice for future wind power development. However, the offshore wind turbine has the characteristics of large capacity, bad working environment, difficult maintenance and so on. The converter is the key component of wind turbine, so it is very important to design a high reliability converter. Because of the high reliability and strong robustness of the squirrel cage induction motor and the decoupling of the motor with the power grid, the interaction between the mechanical drive part and the power grid can be decoupled to a certain extent, which is helpful to improve the reliability of the mechanical part. In this paper, the full power wind turbine based on squirrel Cage induction generator (Squirrel Cage induction generator) is studied. Based on the unit type, the topology, modulation and control strategy for high reliability wind converter are studied. The main work of this paper is as follows: 1) the reliability evaluation method based on the physical failure mechanism of semiconductor devices is used to evaluate the reliability of wind power converter. The influence of wind energy fluctuation and intermittency on the failure rate and life of the converter is analyzed quantitatively, which provides a theoretical basis for improving the reliability of wind power converter design. 2) based on the design of high availability, a system level parallel wind converter topology with redundant functions is proposed, and the reliability of the topology is evaluated, and an economical and optimal redundancy design method for N X parallel wind power converter is proposed. A high reliable design method of distributed control system is proposed for parallel complex large scale power electronic devices. At the same time, the operation, control and protection control strategy of the parallel wind power converter are studied to realize the reoperation of the limited power of wind turbine after the fault reconstruction of the converter. 3) based on the reliability mechanism that reducing the average junction temperature of power devices can prolong the life of the converter, an interleaving parallel modulation method based on DPWM is proposed to maximize the power switching loss and thus reduce the average junction temperature. Improve the reliability of the converter. In this paper, the problems of harmonic and zero sequence circulation caused by interleaving and parallel connection based on DPWM are analyzed, and the optimal modulation and control strategies are put forward to ensure the performance of wind power converter. The reliable operation ability of the converter is greatly improved. 4) the thermal control technology of reactive circulation and orthogonal circulation between subsystems in parallel converter is proposed, and two state control methods based on thermal control are studied. Based on the reliability mechanism that smooth junction temperature fluctuation of power devices can prolong the life of converter, a smooth control of junction temperature fluctuation based on the circulation heat control technique is put forward, aiming at smoothing junction temperature fluctuation. Again, because the sudden drop of wind energy will cause condensation phenomenon in the tank, the condensation phenomenon can be prevented by slowing down the falling speed of the junction temperature based on the circulation heat control technology, thus reducing the failure rate of the converter. It also improves the reliability of the converter. In this paper, the control strategy and modulation method mentioned above are analyzed theoretically, the mathematical model and the simulation results are verified.
【学位授予单位】：上海交通大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM46

【参考文献】