【作者】 万鹏；

【导师】 熊健；

【作者基本信息】 华中科技大学 ， 电力电子与电力传动， 2013， 硕士

【摘要】 PWM整流器具有输入电流正弦、输入电流谐波含量低、功率因数高、输出直流电压纹波小和电能可双向流动等优点，本文研究了三相电压型PWM整流器。建立数学模型是研究三相PWM整流器的有效手段，在三相电网电压平衡下，分别建立了三相电压型PWM整流器在三相ABC坐标系、dq旋转坐标系下的数学模型。为保证整流器性能实现需要动态获取电网电压相位信息，在电网平衡条件下，基于DSP软件方式推导了三相数字锁相环的模型及参数设计方法，考虑到三相不平衡条件下电网电压存在负序分量，对电网平衡条件下的三相锁相环实现方式进行了改进。基于稳态方程关系的整流器传统间接电流控制方式具有良好的静态性能，但电流动态响应较差。从模型原理出发指出了传统间接电流控制动态性能欠佳的本质原因，为改善传统间接电流控制稳定性与动态响应，提出了加入LdI/dt串联补偿的间接电流控制方案，通过在控制环路的前向通道加入一对零点补偿整流器控制对象中的一对大惯性极点。仿真与实验结果说明加入串联补偿后整流器的稳定性有了很大提高，电流的动态响应加快且振荡减小。阐述了基于同步旋转dq坐标系下PWM整流器采用双闭环控制的前馈解耦控制策略，分析了直接电流控制双闭环控制器参数设计方法，实现d、 q轴电流单独控制。三相电压型PWM整流器不平衡控制所实现的控制目标分成两类：一是网侧电流对称控制策略，在dq旋转坐标系下控制整流器网侧电流为对称三相正弦电流。二是消除直流电压脉动的功率平衡控制策略，研究并实现了在dq旋转坐标系下基于网侧功率控制，电网不平衡时三相电感阻抗压降不平衡，虽然网侧功率平衡，但整流桥侧功率仍为不平衡，直流电压纹波仍较大，因此本文还实现了基于整流桥侧功率平衡控制，仿真和实验结果表明基于整流桥侧功率平衡控制可以更好地消除直流电压中的谐波。更多还原

【Abstract】 PWM rectifier has the advantages of sinusoidal input current waveform, high powerfactor, low harmonics distortion of the input current, little output DC voltage ripple, quickdynamic response and also bi-directional power flow. This paper dwells on the research ofthe three phase voltage PWM rectifier.Mathematical modelling is an effective method employed in three phase PWM rectifierresearch. Under the balanced system of three-phase power grid voltage, this paperconstructed the mathematical models of three phase voltage PWM rectifier in staticthree-phase ABC coordinates and also in rotary two-phase coordinates respectively.The grid voltage phase should be dynamically acquired to achieve efficient activepower control as well as reactive power control of the rectifier grid side. Under thecircumstance of a balanced three phase power network, the three-phase digitizedphase-locked loop model and its parameter design are deduced with DSP software.Considering the electromotive force of negative sequence currents under the unbalancedthree-phase voltage condition, the realization algorithm of three-phase phase-locked loopunder the balanced grid system is revamped and improved, with the collected simulationresults that have confirmed its feasibility.Indirect current control of rectifier conducted based on the steady-state equations ownsexcellent static performance, while its current dynamic response is relatively poorer. Fromthe principle of mathematic model we pointe out the unsatisfactory nature of traditionalindirect current control dynamic performance essential reasons.Series Compensation,toimprove the the traditional indirectly current control stability and dynamic response,thisarticle proposes a series compensation of indirect current control scheme by adding LdI/dtwhich adding one pair of zero to compensate the large inertia poles of rectifier naturalcharacteristics in the front of the control loop.Simulation and experimental results showthat adding series compensation has greatly improved the stability of the rectifier andaccelerated the dynamic response of the current speed and decreased the oscillation.This paper elaborates feedforward decoupling double-loop control strategy of PWM rectifier control based on Synchronous rotating coordinate, analysis the parameter designmethod of direct current control dual closed-loop control, and achieves independent controlof the d、 q component current.This paper achieves a variety of unbalanced control strategys based on themathematical model of the three-phase voltage-type PWM rectifier, with the difference ofthe control objective,these strategys can be divided into two categories: one is AC currentsymmetry control strategy, eliminating the negative sequence current to make AC currentsymmetry, and the other is power balance control strategy,aim for eliminating the harmoniccomponent of the dc output voltage. As the three-phase voltage unbalance leads tothree-phase inductor impedance voltage drop unbalanced, although the network side of thepower is balanced, the rectifier bridge side power is still unbalanced, and dc side busvoltage ripple is still large.So this paper also achieves power balance control based on therectifier bridge side. Simulation and experimental results show that the dc voltage pulsationcan be eliminated completely by using the power balance control strategy based on therectifier bridge side.更多还原