感应电机风电机组全功率变流器控制和优化

发布时间：2018-08-06 08:04

【摘要】：随着日益加剧的环境污染和能源短缺问题，风能作为最有发展空间的可再生洁净能源之一，近年来在全球范围内得到广泛开发，从而带动了风力发电技术的快速发展与不断创新。在风力发电机组中，基于鼠笼感应发电机的全功率型变流器风电机组以其结构简单、可靠性高、维护成本低等优点得到广泛应用，尤其在海上风电领域已成为普遍采用的一类机型。针对鼠笼感应电机风电机组全功率变流器，传统控制策略存在稳定性、控制性能、效率与可靠性方面的明显不足。因此，进一步优化全功率变流器性能，提高机组控制性能、效率与可靠性具有重要意义。本文分别从以下几个方面讨论该类型机组的控制与优化问题。 1．对于采用LCL滤波器的网侧变流器，为改善控制系统稳定性能并提高控制器应对参数变动以及外部扰动的鲁棒性，提出了一种基于滑模技术的网侧变流器控制系统设计方案。文章通过建立网侧电流多阶误差方程，在此基础上设计了电流滑模控制器；并提出用PI调节器直流母线电压外环与滑模电流内环的级联式控制结构，由此设计了采用LCL滤波器的网侧变流器控制系统。仿真与实验结果验证了滑模控制器能达到控制要求并具有很好的鲁棒性。 2．对于机侧变流器，为提高控制性能、增加可靠性并降低硬件成本，对感应发电机无速度传感器的观测技术进行研究，提出一种基于离散输入的闭环转子磁链观测器的设计方案，给出一组用线性矩阵不等式描述的约束条件以保证观测误差渐近稳定；基于模型参考自适应方法研究发电机转速估计的工程实现方案。详细探讨了观测器设计中直流偏置的抑制方法。仿真与实验结果验证了磁链观测器设计以及无速度传感器控制实现方案的有效性。 3．为提高直流母线电压动态响应速度，减少母线电容容量，研究了直流母线电压波动抑制的优化控制方案。建立了机组整体欧拉-拉格朗日模型，以无源性控制理论为基础，设计了机侧、网侧变流器联合控制器，并通过对系统平衡点的优化配置改善系统动态性能。针对实际应用中由于模型参数不确定导致无源性控制性能下降的问题，，提出具有L2增益抑制的无源性控制器参数设计方法。分析机组快速性能的约束条件，提出采用功率斜率控制方法进一步优化系统的动态性能。仿真与实验结果验证了所提出控制方法的有效性。 4．为提高机组发电效率、降低系统损耗，提出一种基于系统损耗模型的节能优化控制方案。同时考虑含铁芯损耗的感应发电机损耗模型以及功率变流器的损耗模型，在不同风速下，建立发电机转速、转矩与转子磁链的最优工作点，将其应用到机侧变流器的矢量控制中；并对不同风速时机组采用节能算法下的损耗情况与优化效果进行了分析。实验结果验证了理论方法正确性。 5．为抑制机组稳态工况下功率的低频波动以及提高故障工况下机组的低电压穿越能力，提出采用超级电容储能系统来改进机组并网性能，给出了超级电容储能系统参数的设计方案，并提出系统稳态情况下抑制功率低频波动的协调控制方案以及电网故障情况下低电压穿越的协调控制方案。对协调控制中各变流器环节的控制算法以及切换过程进行了详细描述。仿真验证了参数设计方案以及系统协调控制方案的正确性。
[Abstract]:With the increasing environmental pollution and energy shortage, wind energy, as one of the most developed renewable clean energy sources, has been widely developed in the world in recent years, which has led to the rapid development and continuous innovation of wind power generation technology. In wind turbines, the full power variable flow based on the squirrel induction generator The wind turbine has been widely used for its advantages of simple structure, high reliability and low maintenance cost, especially in the field of offshore wind power. In view of the full power converter of the squirrel cage induction motor wind turbine, the traditional control strategy has the obvious deficiencies in the aspects of stability, control performance, efficiency and reliability. Therefore, it is of great significance to further optimize the performance of the full power converter, improve the control performance of the unit, and the efficiency and reliability. This paper discusses the control and optimization of this type of unit from the following aspects.
1. for the network side converter using LCL filter, in order to improve the stability of the control system and improve the robustness of the controller's response to the change of parameters and the external disturbance, a design scheme of the control system of the grid side converter based on sliding mode technology is proposed. The sliding mode controller is used to control the cascade control structure of the DC bus voltage outer loop and the sliding mode current inner loop of the PI regulator, and the control system of the grid side converter using the LCL filter is designed. The simulation and experimental results show that the sliding mode controller can achieve the control requirements and have good robustness.
2. for the side converter, in order to improve the control performance, increase the reliability and reduce the cost of hardware, the observation technology of the induction generator without speed sensor is studied. A design scheme of the closed loop rotor flux observer based on discrete input is proposed. A set of constraints described by linear matrix inequalities is given to ensure the observation. The error is asymptotically stable; based on the model reference adaptive method, the engineering implementation of the generator speed estimation is studied. The suppression method of the DC bias in the observer design is discussed in detail. The simulation and experimental results verify the design of the flux observer and the effectiveness of the implementation of the speed sensorless control scheme.
3. in order to improve the dynamic response speed of DC bus voltage and reduce the capacity of busbar capacitance, the optimal control scheme of DC bus voltage fluctuation suppression is studied. The overall Euler Lagrange model of the unit is established. Based on the theory of passivity control, the joint controller of the machine side and the network side converter is designed, and the optimization of the balance point of the system is achieved. In order to improve the dynamic performance of the system, the passive controller parameter design method with L2 gain suppression is proposed to reduce the passive control performance due to the uncertainty of the model parameters in practical applications. The constraint conditions of the fast performance of the unit are analyzed, and the power slope control method is proposed to further optimize the dynamics of the system. The simulation and experimental results verify the effectiveness of the proposed control method.
4. in order to improve the generating efficiency and reduce the loss of the system, an energy-saving optimization control scheme based on the loss model of the system is proposed. At the same time, the loss model of induction generator with iron core loss and the loss model of the power converter are considered. The optimal working point of the generator speed, torque and rotor flux is established under different wind speeds. This paper uses the vector control of the side converter, and analyzes the loss situation and the optimization effect of the energy saving algorithm with different wind speeds. The experimental results verify the correctness of the theoretical method.
5. in order to restrain the low frequency fluctuation of power in the steady state of the unit and improve the low voltage crossing ability of the unit under the fault condition, the super capacitor energy storage system is proposed to improve the performance of the unit grid connection. The design scheme of the parameters of the super capacitor energy storage system is given, and the coordination control of the low frequency fluctuation of power under the condition of the system stability is put forward. The scheme of the system and the coordinated control scheme of low voltage crossing under the condition of power grid fault. The control algorithm and the switching process of each converter link in the coordinated control are described in detail. The simulation verifies the correctness of the parameter design scheme and the system coordination control scheme.
【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】：TM315;TM46

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