【作者】 王要强；

【导师】 孙力；

【作者基本信息】 哈尔滨工业大学 ， 电机与电器， 2013， 博士

【摘要】 随着煤、石油、天然气等常规资源的日渐枯竭、未来能源和电力需求的持续增加以及全球生态环境的不断恶化，新能源并网发电已经成为能源和电气工程领域的研究热点。并网逆变系统作为发电源与电网的接口装置，其性能的优劣直接会对注入电网电能的质量产生影响，是整个发电设备的关键环节。本文以三相电压型并网逆变系统为研究对象，主要围绕LCL滤波器参数的设计与优化、采用LCL滤波器的并网逆变系统的控制策略以及复杂电网环境下的电网电压信息同步检测与系统持续运行能力的提升等问题展开研究，并结合项目背景，通过构建的微型燃气轮机半物理并网发电系统实验平台对论文的研究成果进行实验验证。论文首先建立系统的一般数学模型以及系统在理想、不平衡、畸变不同电网电压约束条件下的数学模型。指出不平衡、畸变电网环境下传统电网电压信息检测算法的局限性，提出基于交流幅值积分的宽适应范围电网电压信息同步检测算法。提出的算法适用于不平衡、畸变的电网环境，可以有效抑制谐波干扰、提取电网电压基波正、负序分量，从而实现其相角、频率和幅值信息的同步检测。建立的系统模型和提出的电网电压信息同步检测算法为论文后续的研究奠定基础。建立LCL滤波器的等效模型，深入分析其工作特性，揭示滤波器参数及参数间关系与滤波器工作特性的内在联系，提出LCL滤波器参数的优化设计方案。方案首先给出滤波器参数计算的依据与思路，然后列出参数选取的准则与步骤，最后围绕滤波器的谐波抑制性能、参数及其配合关系以及阻尼损耗等问题对滤波器参数进一步优化。提出的方案能够反映滤波器参数及参数间关系影响滤波器工作特性的趋势和强度，并且兼顾了滤波器的谐波抑制性能和阻尼电阻的功率损耗等问题，可以在相同总滤波电感值下获得更好的滤波效果，同时降低阻尼电阻的功率损耗，提升系统运行的效率。针对采用LCL滤波器的并网逆变系统的控制策略，首先建立其复频域模型，分析系统电流控制回路反馈变量的自由度，并分别指出网侧电流和逆变器侧电流闭环控制策略各自存在的问题。为解决逆变器侧电流闭环控制策略存在的并网电流相角滞后问题，分析问题产生的根源，并定义控制复阻抗的概念，更新逆变器输出电流的参考指令，从而提出基于控制复阻抗前馈的复合间接电流控制策略。提出的控制策略通过逆变器侧电流闭环控制间接实现了对并网电流的调节，消除了传统逆变器侧电流闭环控制策略存在的并网电流相角滞后现象，提升了系统的运行效率，并且稳定性好，便于系统集成，同时不需要增加额外的传感器。为增强系统在不平衡、畸变电网环境下的适应性，分析单基波正序同步旋转坐标系下系统电流控制回路存在的问题，并定义比例混合积分的概念。针对电网电压不平衡的影响，提出基于P+NSHI的并网功率脉动抑制策略。然后提出基于P+HHI的并网电流低频谐波抑制策略，提升系统对电网电压背景谐波的抗扰能力。最后提出基于P+NSHHI的强电网环境适应性系统控制策略。提出控制策略的电流控制回路只在基波正序同步旋转坐标系下进行，无需电流反馈信号基波正、负序及各次谐波分量的分解，降低了系统控制的复杂度。提出的控制策略可以实现逆变器输出电流基波正、负序及谐波分量的无静差控制，抑制了并网功率脉动，改善了并网电流的波形质量，有效提升了系统适应复杂电网环境持续运行的能力。最后，结合论文的理论和仿真研究，通过构建的微型燃气轮机半物理并网发电系统实验平台进行实验研究，验证和评价论文提出的算法、方案和控制策略，实验结果证明了论文理论分析的正确性和提出方法的有效性。更多还原

【Abstract】 With the exhausting of conventional resources such as coal, oil and naturalgas, the increasing of energy and electricity demands and the deteriorating ofglobal ecological environment, the grid interfaced power generation of newenergy has become a hotspot in the field of energy and electrical engineering.The grid interfaced invertion system, as the interface unit of generation sourceand grid, the performance of which directly impacts the energy quality injectedinto grid, is a key component of the entire generation equipment. This thesis willtake the three-phase voltage source grid interfaced invertion system as researchobject, conducting research on parameter design and optimization of LCL filter,control strategy of system with LCL filter, grid voltage information synchronousdetection and continuous operation ability enhancement of system undercomplicated grid conditions. And also, combined with the project background,an experimental platform of the hardware-in-the-loop generation system ofmicro gas turbine for grid integration is constructed to verify the research resultsof this thesis.Firstly, for the grid interfaced invertion system with LCL filter, a generalmathematical model and models under ideal, unbalance, distortion various gridvoltage constraints are built. Based on this, limitations of the conventional gridvoltage information detection algorithm under unbalanced and distorted gridconditions are indicated, and then a novel grid voltage information synchronousdetection algorithm based on AC amplitude integral is proposed, which has awide grid condition adaptation range. The proposed algorithm is compatible tothe unbalanced and distorted grid conditions, which can restrain the harmonicinterference, extract the fundamental positive and negative components of gridvoltage, consequently detect their information of phase angle, frequency andamplitude synchronously. The built system model and proposed grid voltageinformation detection algorithm lay a foundation for the subsequent researches.The equivalent model of LCL filter is built and its operating characteristicsis analyzed, revealing the relationship between the filter parameters, theirrelationships and the filter operating performance. Based on this, anoptimization design program of LCL filter parameters is proposed. In theprogram, the basis and idea of parameter calculation are demonstrated, and thenare the criteria and steps of the filter parameter selection procedure, at last, thefilter parameters are further optimized regarding to the harmonic suppression performance, parameters and their cooperation relationships, power loss on thedamping resistor, etc. The proposed program can reflect the impact trend andstrength of the filter parameters and their relationships on filter operatingperformance, in addition, both the harmonic suppression performance anddamping loss problem are considered. A better filtering performance can beobtained with the same total inductance value, and the power loss on thedamping resistor reduced, leading to the system efficiency enhanced.For the control strategy of grid interfaced invertion system with LCL filter,the system model of complex frequency domain is built, and the feedbackvariable degrees of freedom of the current control loop are analyzed, pointingout problems of the control strategy based on grid and inverter side currentclosed-loop respectively. In order to solve the problem of phase angle lag of gridcurrent of the conventional inverter side current closed-loop control strategy, thecause of which is analyzed, and then a concept of controlled complex impedanceis defined to update the reference signal of inverter output current, thus acompounded control strategy of indirect current based on feedforward ofcontrolled complex impedance is proposed. With the proposed control strategy,the grid current can be controlled indirectly through inverter side current closed-loop. The proposed control strategy has a good stability, facilitates the systemintegration, and needs no more additional sensors, what’s more, can eliminatethe phase angle lag of grid current in the conventional inverter side currentclosed-loop control strategy.In order to improve the system adaptability to unbalanced, distorted gridconditions, problems of the current control loop in fundamental positivesequence single synchronous rotating frame (FPS-SSRF) is analyzed, and aconcept of proportion plus hybrid integration is defined. Aiming at the impact ofunbalance in grid voltage, a grid power pulsation suppression strategy based onproportion plus negative sequence hybrid integration is proposed. Afterwards, alow frequency grid current harmonic suppression strategy based on proportionplus harmonic hybrid integration is proposed to enhance the system rejectionability to grid voltage background harmonics. Finally, it is the system controlstrategy with high adaptability to grid conditions based on proportion plusnegative sequence and harmonic hybrid integration. All current control loops inthe proposed control strategies above are only implemented in FPS-SSRF, andno extraction of fundamental positive, negative sequence or harmoniccomponents of current feedback signal is needed, leading to the complexity ofsystem control reduced. With the proposed control strategy, the fundamentalpositive, negative sequence and harmonic components of inverter output currentcan be precisely controlled with no static error, the grid power pulsation is suppressed and the waveform quality of grid current is improved, leading tocontinuous operation ability of system with high adaptability to complicated gridconditions elevated effectively.Finally, combined with the theoretical and simulation researches in thisthesis, an experimental platform of the hardware-in-the-loop generation systemof micro gas turbine for grid integration is constructed, and experimentalresearch is conducted on the platform to verify and evaluate the proposedalgorithms, programs, and control strategies. Experimental results demonstratethe correctness and effectiveness of the theoretical analyses and proposedmethods in this thesis.更多还原