【作者】 史明明；

【导师】 周波；

【作者基本信息】 南京航空航天大学 ， 电力电子与电力传动， 2012， 博士

【摘要】 变速恒频发电技术是微型燃气轮机发电、风力发电、小型水力发电等分布式发电系统的重要发展方向，发电机与功率变换器是其不可缺少的两个关键部件。混合励磁同步发电机兼具永磁电机的高效率和电励磁电机励磁可控的优点，具有较宽的转速适应范围，在变速恒频分布式发电系统中具有良好的应用前景。矩阵变换器没有中间直流储能环节，可同时实现正弦化的输入电流与输出电压，具有结构紧凑、功率密度高的优点。因此，混合励磁同步发电机与矩阵变换器两者的结合，有利于提高发电系统的功率密度与可靠性，是变速恒频分布式发电的一种优化组合。本文的研究内容主要围绕基于矩阵变换器与混合励磁同步发电机组合的变速恒频分布式发电系统的控制技术展开，采用理论分析、仿真研究和实验验证相结合方法，重点对矩阵变换器的调制策略、并网控制技术、有源阻尼控制技术以及发电系统运行的闭环控制方法进行研究。矩阵变换器的调制策略是保障其稳定运行的基础，本文深入研究了矩阵变换器瞬时值双线电压合成调制策略，针对矩阵变换器输入输出扇区组合数较多，控制实现复杂的特点，提出了一种新型扇区划分规则，通过引入表征输入参考相电压极性的变量，将输入扇区的划分规律与输出扇区的划分规律有机结合，使输出电压扇区由6个减少为3个，从而将扇区组合数由传统的36种减少为18种，简化了瞬时值双线电压合成策略的数字化实现过程。矩阵变换器的并网控制是实现变速恒频分布式发电系统并网运行的前提。本文将矩阵变换器的瞬时值双线电压合成调制策略与基于电网电压定向控制的并网电流控制方法相结合，研究了矩阵变换器交交直接并网控制方法。为解决矩阵变换器实际开关调制过程中存在的窄脉冲对换流安全性与并网电流质量都影响较大的问题，本文在分析正常脉冲状态与窄脉冲状态基础上，提出了一种基于双边斩波与单边斩波相结合的混合斩波方式的窄脉冲补偿方法，对于正常脉冲状态采用双边斩波方式，对于窄脉冲状态采用单边斩波方式，较大程度地减少了影响换流安全性的窄脉冲数量。对于单边斩波模式下仍不能够完成四步换流过程的窄脉冲，根据伏秒积分平衡原则，在屏蔽窄脉冲的同时对其它脉冲的作用时间进行修正，从而保证输出电压在一个开关周期内的平均值不变，有效地减小了并网电流的畸变。针对矩阵变换器的输入源为发电机的运行情况，本文研究了利用发电机电枢绕组电感与外接电容构成LC滤波器的方案，减小了滤波器的体积重量。通过建立矩阵变换器系统的小信号状态方程，利用李亚普诺夫稳定性理论对输入滤波器、矩阵变换器、感性负载中各参数的变化对系统稳定性的影响进行了分析。在此基础上，为提高系统的稳定运行区域，解决系统内在的不稳定原因所起的电枢电流震荡问题，提出了一种基于谐波电流比例微分前馈控制的有源阻尼控制策略，提高了系统的稳定性，降低了谐波震荡分量。在混合励磁同步发电机与矩阵变换器组合的发电系统中，具有励磁电流和矩阵变换器调制比两个系统控制变量。针对这一优势，本文提出了应用于该发电系统的两级式闭环控制策略，前级利用励磁电流对发电机端电压进行闭环控制，降低了原动机转速波动对矩阵变换器输入输出性能的影响。后级矩阵变换器的变调制比闭环控制可根据不同的运行情况选择不同的闭环控制方式，在独立发电运行时，后级矩阵变换器采用输出电压瞬时值闭环控制方式；在并网发电运行时，后级矩阵变换器采用输出电流瞬时值闭环控制方式。矩阵变换器快速的电压电流调节能力，提高了发电系统的动态性能。最后，本文设计并实现了以数字信号处理器和可编程逻辑控制器为核心的数字化变速恒频分布式发电系统的实验平台，利用该平台验证了本文方法的可行性和正确性，并为进一步研究提供了可靠的实验条件。更多还原

【Abstract】 Variable speed constant frequency (VSCF) generation technology becomes a main trend indistributed generating application such as micro-turbines generation, wind energy conversion, smallhydroelectric generation etc. Generator and power converter are two indispensable componentsapplied in VSCF generation system. Hybrid Excitation Synchronous Generator (HESG) combinespermanent-magnet and electrical excitation sources, and possesses the merits of high efficiency andcontrollable air-gap magnetic field. Thereby, HESG is a preferred candidate in VSCF generationsystem for a wide-speed range operation. Matrix Converter (MC) is a kind of AC/AC converter withthe features such as the compact size, high power density and the absence of the intermediate DC linkfor energy storage. It achieves sinusoidal input and output waveforms simultaneously. As a result, theintegration of the HESG and the MC is a favorable choice for VSCF generation system.This paper focuses on the control technologies of HESG-MC based variable speed distributedgeneration system. Several methods, such as theoretical analysis, digital simulation and experimentverification, are adopted in a series of studies on MC modulation scheme, grid connected control,active damping control and closed-loop control method for the HESG-MC generation system.The modulation scheme is the core of MC control strategies. In this paper, the double line-to-linevoltage synthesis (DLLVS) modulation scheme which is based on the instantaneous value of the inputline-to-line voltage is fully studied. As there are various combinations of input and output sectors inMC, a novel sector division regular is proposed to simplify the digital realization of DLLVS method.By introducing a parameter which indicates the pole of input determinate phase voltage, the inputsector division is interrelated with output sector division. A novel output sector division regular isproposed to reduce the output sectors from6to3, and also reduce number of sector combinationsfrom36to18.The grid-connected control for matrix converter is the premise for distributed variable speedgeneration. This paper studies the DLLVS modulation strategy and grid voltage oriented currentcontrol method for operation of grid-connected matrix converter. The problem of narrow pulses inMC is unavoidable because of existing modulation algorithm performance. Narrow pulses may affectcommutation safety and cause non-linearity distortion especially when MCs are applied as gridconnected converters. The problem of narrow pulse was analyzed in this paper. Based on the normaolpulse state and narrow pulse state, a dual side and single side hybrid chopping pattern is explored to compensate the narrow pluses, depressing the distortion in grid connected current effectively. Thismethod chooses dual side chopping pattern for normal pulses, and single side chopping pattern fornarrow pluses, largely reduced the numbers of narrow pluses which may cause commutation problems.For narrow pluses which still can not fininsh a whole four step commutation, a compenstation methodis adopted. The compensation guarantee the average value of output voltage do not change by updatedduty ratio.To obtain a good performance of the MC, it is necessary to design an input LC filter to smooththe input currents. The supply source of MC is a generator in this proposed generation system, so thearmature windings of the generator are used as the filter inductors. In this way the volume and weightof LC filters can be reduced. Additionally, the stability of MC system is concerned, by establishing thesmall signal molde for LC filter, matrix converter and inductive loads, the Lyapunov stability theory isutilitized to analyze the relation of parameter variation and system stable region. Based on thestability analysis, an active damping control with proportion and derivative fed forward algorithm isalso investigated for better performance and stability.In HESG-MC variable speed generation system, excitation current and modulation ratio are twocontrollable variables. Based on these variables, a two-stage closed loop control scheme is proposed.The preceding stage is a generator terminal voltage closed loop control, which is realized byregulating excitation current, reduced the influence of speed fluctuation on MC performance. Thebackward stage is an instantaneous value closed loop control of MC, and MC can choose currentclosed loop control or voltage closed loop control, whch based on the operation state of distributedgeneration system. The backward control can achieve fast output voltage and current adjustment andgood dynamic performance of generation system.Finally, the experimental platform of the HESG-MC variable speed distributed generation systemis constructed, and the software control core is realized in digital signal processor (DSP) and complexprogrammable logic device (CPLD). The proposed VSCF generating system topology and itsfeasibility are verified on the prototype. The platform also provides a reliable basis for future research.更多还原