基于级联多电平逆变器的EPT及其控制策略

发布时间：2018-07-07 13:48

本文选题：电子电力变压器 + 单极倍频载波移相SPWM　；参考：《华中科技大学》2014年硕士论文

【摘要】：随着人们对电力供电品质要求的提高以及电网智能化的不断发展，传统电力变压器由于其匮乏的控制手段以及其不可靠的电能质量，使得其并不能很好的承担智能电网的新要求。正是在这样一种背景下，一种结合了现代电力电子技术的电子电力变压器(Electronic Power Transformer，EPT)逐渐发展起来了。它可以实现对变压器原副方以及内部电能的完全控制，完全改变传统电力变压器的运行和控制方式，能够改善电网稳定性以及电能质量，因此EPT的研究对电力系统的建设具有重要意义。本文针对升压型EPT输出逆变侧高电压大功率的特点，提出了应用级联多电平逆变器的EPT拓扑结构，并选择了单极倍频载波移相技术(Carrier phase-shifted SPWM,CPS-SPWM)作为其调制策略，使得装置输出能够在较低开关频率下取得较高的等效开关频率，，具有较好的谐波特性，并且可以简化输出滤波。对于EPT的控制策略，文中着重讨论了在有源和无源两种情况下级联型多电平逆变侧的控制器的设计，在PARK变换的基础上提出了一种基于电压电流双闭环状态反馈解耦控制，并在MATLAB/Simulink平台下搭建了仿真模型，验证了这种反馈解耦的控制策略动态响应比较快，而且稳定后无静差。在前面的基础上，研制了基于单极倍频CPS-SPWM级联7电平逆变器的EPT的实验装置，采用DSP控制芯片作为EPT控制系统的核心单元来完成信号采样及控制计算工作等等。实验结果表明，此EPT装置能够灵活调节输入输出电气量，保持输出电压恒定的功能，具有良好的工业应用前景。
[Abstract]:With the improvement of power supply quality and the continuous development of intelligent power grid, traditional power transformers are lack of control means and unreliable power quality. Make it not very good to meet the new requirements of the smart grid. It is under such a background that a kind of electronic power transformer (EPT) which combines modern power electronics technology has been developed gradually. It can realize the complete control of the original, auxiliary and internal electric energy of the transformer, completely change the operation and control mode of the traditional power transformer, and can improve the stability of the power network and the power quality. Therefore, the research of EPT is of great significance to the construction of power system. In view of the high voltage and high power characteristics of boost EPT output inverter, this paper presents the EPT topology using cascaded multilevel inverter, and selects Carrier phase-shifted SPWMN CPS-SPWM (Carrier phase-shifted SPWMN CPS-SPWM) as its modulation strategy. The device output can obtain higher equivalent switching frequency at lower switching frequency, has better harmonic characteristics, and can simplify the output filtering. For the control strategy of EPT, the design of cascaded multilevel inverter side controller in both active and passive cases is discussed. Based on the park transform, a voltage and current double closed loop state feedback decoupling control is proposed. The simulation model based on MATLAB / Simulink platform is built to verify that the dynamic response of the feedback decoupling control strategy is fast and there is no static error after stabilization. On the basis of the above, an experimental device of EPT based on CPS-SPWM cascaded 7-level inverter is developed. DSP control chip is used as the core unit of EPT control system to complete signal sampling and control calculation. The experimental results show that the EPT device can flexibly adjust the input and output electrical quantities and keep the output voltage constant. It has a good prospect of industrial application.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM464

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