【作者】 王宇；

【导师】 许建平；

【作者基本信息】 西南交通大学 ， 电气工程， 2023， 硕士

【摘要】 整流器广泛应用于有源滤波与无功补偿、新能源并网发电、四象限电机驱动、超导储能技术等场合。如何实现整流器的高功率因数、高效率、高功率密度和低输入电流畸变是当今研究的重点。本文以三相六开关PWM整流器为研究对象,介绍了常用的控制策略和调制策略,分析了整流器的工作模态,建立了整流器三个坐标系的数学模型和等效电路。本文选用dq前馈解耦平均电流控制,添加电流前馈实现d轴和q轴电流的解耦,添加占空比前馈提高电流环路的跟踪能力和动态响应能力。分析了叠加零序注入信号的CBPWM调制与各类连续、不连续空间矢量脉宽调制(Space Vector Pulse Width Modulation,SVPWM)的等效性,叠加零序注入信号的CBPWM调制实现方式简单,拥有线性调制范围宽和直流电压利用率高的优点。研究了对称七段式调制、六步法PWM调制和三步法PWM调制的三种不同零序注入信号。分析了考虑电感电流纹波和开关器件寄生电容,使用不同调制策略时死区电压误差和注入电流谐波的表达式。死区时间给三相六开关PWM整流器的电感电流注入6k±1次的低次谐波,三步法PWM调制额外注入偶次电流谐波。介绍了传统的两电平、三电平和梯形补偿等基于平均值理论的前馈死区补偿策略,补偿参数的整定需要大量离线计算,鲁棒性低。本文提出了一种自适应前馈补偿策略,根据三角函数的正交性,从d轴和q轴电流误差信号中提取需要补偿的低次谐波,利用锁相环提供的相位信息构建补偿算法,获取自适应变化的补偿信号,实现对提取电流谐波的补偿。该策略鲁棒性强、对特定电流谐波补偿效果好。将电感电流纹波和开关器件寄生电容的影响纳入考虑,改进了自适应补偿算法以获得更好的补偿性能。研究了基于内模原理的选择性谐波重复控制,实现对nk±m次电流谐波的补偿。根据分数阶思想使用拉格朗日插值法将滞后环节中存在的小数部分近似成整数多项式,提高环路增益。针对重复控制动态响应慢的缺点,结合插入式重复控制器和比例控制器进行改善。研究了重复控制的低通滤波器、相位补偿器和控制增益的设计和选取,给出了系统稳定性判据。设计了一台3kW的实验样机,介绍了升压电感、直流滤波电容、功率开关器件等硬件参数的选择和软件实现流程,给出了采用不同死区补偿策略的稳态波形和采用插入式重复控制器、比例控制器的动态波形,证明了理论的正确性。更多还原

【Abstract】 The rectifier is widely used in the occasion of active filtering,non-contribution compensation,new energy grid-to-network power generation,four-quadrant motor drive,and superconducting energy storage technology.How to achieve higher power factor and efficiency,higher power density,lower input current distortion is the focus issue of today’s research.For the three-phase six-switch PWM rectifier,introduces the commonly used control methods and modulation strategies,analyzes the working mode of the rectifier,derives the mathematical models and equivalent circuits in three coordinate systems.In this paper,adapts the dq feedforward decoupling average current control,the current feedforward is added to decouple the d-axis and q-axis currents,and the voltage feedforward is added to improve the tracking ability and dynamic response ability of the current loop.Derives the equivalence between CBPWM modulation with zero-sequence injection signal and continuous or discontinuous space vector pulse width modulation(Space Vector Pulse Width Modulation,SVPWM),the CBPWM modulation with zero-sequence injection signal strategy has the advantages of simple implementation,wide linear modulation range and high utilization of DC voltage.Three different zero sequence injection signals corresponding to symmetric seven segment modulation,six-step PWM modulation,and three-step PWM modulation are researched.The expression of deat time voltage error and injected current harmonics when using different modulation strategies considering the three-phase inductance current ripple and parasitic capacitance of switching devices is analyzed.It is found that the dead-time will inject 6k±1 low harmonic component into the inductance current of the three-phase six-switch PWM rectifier,the three-step PWM modulation injects extra even harmonic components.Introduces the traditional two-level,three-level and trapezium compensation feedforward dead-time compensation strategies,the compensation parameters require a lot of offline calculations and the robustness is lowIn this paper,according to the orthogonality of the trigonometric function,proposes an adaptive feedforward compensation strategy,extractes harmonic components from the d-axis and q-axis current error signals,uses the phase information provided by the phase-locked loop to construct a compensation algorithm and obtain the adaptive compensation signal,achieve complete suppression of the extracted harmonic components.It has the advantanges of high robustness and better compensation effect for specific harmonic components.The adaptive compensation algorithm could be improved for better compensation performance by taking into account the effects of the inductance current ripple and parasitic capacitance of switching devices,In this paper,proposes a selective harmonics repetitive control strategy using Internal-model principle to compensate nk±m low harmonic component.According to the fractional order idea,the Lagrange interpolation method is used to rewrite the fractional part in the lag link into polynomial expression to improves the loop gain.Aiming at the disadvantage of slow dynamic response of repetitive control,an improvement is made by combining the plug-in repetitive controller and the proportional controller.Finally,introduces the design and selection of loop gain,low-pass filter,phase compensators and gives the system stability criteria.A 3kW experimental prototype is designed,introduces the hardware parameters of boost inductor,DC filter capacitor,power switch device and software implementation process.The steady-state waveforms using different dead-time compensation strategies and the dynamic waveform of plug-in repetitive controller and proportional controllerare given,which proves the correctness of the theory.更多还原