10kW钒液流储能双向变流器研制

发布时间：2018-08-18 17:41

【摘要】：储能技术的迅速发展，使新能源分布式发电系统大规模并网运行成为可能。钒液流电池作为一种新型环保储能电池，在储能系统中具有广阔的市场应用前景。储能变流器作为电网与储能载体之间的电气接口，关系到整个储能系统的安全稳定运行。因此，对钒液流储能双向变流器的研究具有重要意义。本文首先提出了10kW钒液流储能双向变流器的总体设计方案，选定双向半桥DC/DC拓扑和带LCL滤波器的双向三相桥式DC/AC拓扑构成的多级型储能变流器结构，并简要分析了电路的工作原理。重点研究带LCL滤波器的DC/AC级运行于并网模式时的控制策略，，建立其在dq同步旋转坐标系下的数学模型，由LCL滤波器无源阻尼方案经过系统结构框图等效变换，引出滤波电容电流与并网变流的双闭环控制策略，并对dq两轴进行解耦控制。研究基于期望频率特性的电流双闭环控制器的设计方法，重点分析当系统参数发生变化时，对系统稳定性的影响。提出的设计方法在已知系统参数的情况下，可以准确的计算出内外环的控制器参数，在保证系统性能的同时使系统具有一定的鲁棒性。在理论研究的基础上，对储能变流器的硬件系统和软件系统进行了设计，包括对主电路参数的计算、对DC/DC控制系统和DC/AC控制系统的设计、对外围功能电路的设计、对控制软件的设计以及对上位机界面的设计等。其中详细给出了采样、信号调理、IPM接口、时序控制、保护、状态指示、通讯接口、辅助电源系统等硬件电路的设计方案，详细给出了系统主程序、主中断、通信中断、启停时序、分相启动、单同步坐标系软件锁相环、采样处理、数字PID控制器、参数归一化SVPWM调制算法等软件程序的工作流程。最后，按照设计方案搭建组装了一台10kW钒液流储能双向变流器样机，在调试过程中不断对系统进行优化升级，并进行了一系列实验。仿真实验与样机实验证明所采用的控制策略与设计方法正确有效，储能变流器系统能够在并网逆变、孤网逆变和并网整流三个模式下稳定运行，基本实现了系统的各项功能。
[Abstract]:The rapid development of energy storage technology makes it possible for the large-scale grid-connected operation of the new energy distributed generation system. As a new type of environmental-friendly energy storage battery, vanadium flow battery has a broad market prospect in the energy storage system. Stable operation. Therefore, the research of vanadium liquid storage bidirectional bi-directional converter is of great significance.
Firstly, the overall design scheme of 10 kW vanadium liquid flow energy storage bidirectional converter is presented. The structure of the bidirectional half-bridge DC/DC converter and the bidirectional three-phase bridge DC/AC converter with LCL filter are selected, and the working principle of the circuit is briefly analyzed. The control strategy is established and its mathematical model is established in the DQ synchronous rotating coordinate system. The passive damping scheme of LCL filter is transformed into the equivalent structure block diagram of the system. The double closed-loop control strategy of filter capacitor current and grid-connected converter is derived, and the two axes of DQ are decoupled. The proposed design method can accurately calculate the controller parameters of the inner and outer loops when the system parameters are known. It can ensure the system performance and make the system robust to a certain extent. On the basis of theoretical research, the energy storage converter is studied. The hardware system and software system are designed, including the calculation of main circuit parameters, the design of DC/DC control system and DC/AC control system, the design of peripheral function circuit, the design of control software and the design of upper computer interface. The design schemes of state indication, communication interface, auxiliary power supply system and other hardware circuits are given in detail. The work flow of the system main program, main interrupt, communication interrupt, start-stop sequence, phase-split start, single-synchronous coordinate system software phase-locked loop, sampling processing, digital PID controller, parameter normalized SVPWM modulation algorithm and other software programs are given. A 10 kW vanadium liquid flow energy storage bidirectional converter prototype was built and assembled. During the debugging process, the system was optimized and upgraded, and a series of experiments were carried out.
The simulation and prototype experiment prove that the control strategy and design method are correct and effective. The energy storage converter system can operate stably under three modes: grid-connected inverter, isolated grid inverter and grid-connected rectifier. All the functions of the system are basically realized.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM46

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