大规模风电并网中级联STATCOM的控制方法研究

发布时间：2018-01-16 05:09

本文关键词：大规模风电并网中级联STATCOM的控制方法研究　出处：《湖南工业大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着大规模的风电场投入使用，其并网对电能质量产生的负面影响日趋严重。通过在风电场的出口配备无功补偿装置可以动态补偿系统中的无功功率，稳定并网接入点电压，，提高风电机组低电压和故障穿越能力，减少大规模风电并网对大电网的冲击。故本文针对风电场中级联STATCOM装置的控制方法进行深入研究。首先，系统介绍了高压大容量STATCOM常用主电路拓扑结构，比较它们的优缺点后，得出级联型拓扑的优势所在。利用矢量图分析级联STATCOM的工作原理，对系统主电路参数进行了相关设计，详细分析了单极倍频SPWM调制策略性质并阐述其优点。其次，针对级联STATCOM的直流侧电压难以平衡问题，提出基于有功功率均等分配的直流侧电容电压平衡控制方法。通过调节其交流侧吸收的有功功率来控制直流侧电压的大小，采用分层协调控制策略实现级联STATCOM的整体有功、无功控制，上层采用解耦实现总体有功、无功控制，下层通过模块控制器实现有功功率均等分配控制。仿真和实验结果表明，该方法有效解决了级联STATCOM直流侧电容电压难以平衡的关键问题。再次，针对不平衡工况下级联STATCOM的控制问题，提出基于正序-负序解耦PWM的控制方法。分析了其在不平衡工况下的工作特性，采用让级联STATCOM输出等效负序电压的办法来保证接入点的电压平衡。推导了系统在正序和负序环境下的解耦控制方程，分析其延伸出来的无功补偿和电压控制两种工作模式。根据不平衡度的三个范围，提出分时段补偿控制系统，实现了装置的最大化利用。仿真和实验结果表明，该方法有效确保了级联STATCOM在不平衡工况下的安全稳定运行。最后，对级联STATCOM控制系统进行了软硬件设计。控制硬件平台为双DSP+FPGA+CPLD组合系统，分别对主控制板以及功率单元控制系统进行了硬件设计。利用流程图的方式对控制软件进行了设计，主要包括DSP1及DSP2的主程序和控制中断程序、PWM信号生成及监测软件设计。
[Abstract]:With the large-scale wind farm put into use, the negative impact of grid connection on power quality is becoming more and more serious. Reactive power can be dynamically compensated by installing reactive power compensator at the outlet of wind farm. Stable access point voltage, improve wind turbine low voltage and fault traversing ability. To reduce the impact of large-scale wind power grid connection on large power grid, this paper makes a deep research on the control method of wind farm intermediate STATCOM device. Firstly, the main circuit topology of high voltage and large capacity STATCOM is introduced, and their advantages and disadvantages are compared. The advantages of cascade topology are obtained. The main circuit parameters of the system are designed by using vector diagram to analyze the working principle of cascade STATCOM. The properties and advantages of monopole frequency doubling SPWM modulation strategy are analyzed in detail. Secondly, it is difficult to balance the DC voltage of cascaded STATCOM. A DC side capacitor voltage balance control method based on equal distribution of active power is proposed. The magnitude of DC side voltage is controlled by adjusting the active power absorbed by the AC side. The overall active and reactive power control of cascaded STATCOM is realized by hierarchical coordinated control strategy, and the total active and reactive power control is realized by decoupling in upper layer. The simulation and experimental results show that this method can effectively solve the key problem that the capacitor voltage of cascaded STATCOM DC side is difficult to balance. Thirdly, aiming at the control problem of cascaded STATCOM under unbalanced conditions, a control method based on positive and negative sequence decoupling PWM is proposed, and its working characteristics under unbalanced conditions are analyzed. The voltage balance of the access point is ensured by using cascade STATCOM to output equivalent negative sequence voltage. The decoupling control equations of the system in positive sequence and negative sequence environment are derived. The extended reactive power compensation and voltage control modes are analyzed. According to the three ranges of unbalance, the compensation control system is put forward, which realizes the maximum use of the device. The simulation and experimental results show that. This method effectively ensures the safe and stable operation of cascaded STATCOM under unbalanced conditions. Finally, the software and hardware of the cascade STATCOM control system are designed. The control hardware platform is a dual DSP FPGA CPLD integrated system. The main control board and power unit control system are designed respectively. The control software is designed by flow chart, including the main program of DSP1 and DSP2 and the control interrupt program. PWM signal generation and monitoring software design.
【学位授予单位】：湖南工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM614

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