电力电子变压器控制策略研究

发布时间：2018-07-10 14:55

本文选题：电力电子变压器 + 智能电网　；参考：《辽宁工程技术大学》2017年硕士论文

【摘要】：电力电子变压器(PET)是结合电力电子变换技术和高频电能变换技术的新型变压器。它不仅可以实现传统变压器的变换电压等级、电气隔离等作用,并且体积与重量小,能对变压器的原副边电压的相位与幅值进行有效的控制,并且能够抑制故障和谐波的流动。将电力电子变压器运用于电力系统能够保证电能的质量,使系统的可控性得到提升,并且有利于分布式电源并入电网,符合智能电网的建设。因此研究PET在理论方面和实际应用都有重要的意义。本文首先对PET的工作原理与一些经典的拓扑结构进行了介绍,着重对AC/DC/AC型PET进行研究,并分别研究了各级电路的控制策略。输入级使用的是前馈解耦的电压电流双闭环控制,隔离级直接使用开环控制,输出级使用的是电压闭环的控制。为了加快动态响应速度,适用于需要快速动态响应的场合,本文将预测直接功率控制(P-DPC)应用于PET的输入级,和空间矢量脉宽调制相结合,可以固定开关频率。之后对P-DPC控制进行了改进,消除了稳态误差,能够适应有更高要求的场合。通过在ulinkMatlab/Sim对PET的各级电路分别建立了仿真模型,并且输入级分别使用了双闭环解耦控制和改进的预测直接功率控制,并对PET的整体在不同的工作情况下进行仿真。最后对PET系统的硬件和软件进行了设计,搭建了实验平台。仿真与实验结果证明了电力电子变压器的优点和将预测直接功率控制策略应用在电力电子变压器的可行性以及其它各环节控制策略的正确性。
[Abstract]:Power electronic transformer (PET) is a new type transformer which combines power electronic transformation technology and high frequency power conversion technology. It can not only realize the function of transformer's conversion voltage grade and electrical isolation, but also can control the phase and amplitude of transformer's primary and secondary side voltage effectively, and restrain the flow of faults and harmonics. Applying power electronic transformers to power system can ensure the quality of power, improve the controllability of the system, and facilitate the integration of distributed power sources into the power grid, which is in line with the construction of smart grid. Therefore, the study of PET in theory and practical applications are of great significance. In this paper, the principle of PET and some classical topologies are introduced. The AC / DC / AC type PET is studied, and the control strategies of various circuits are studied. The input stage uses the feedforward decoupling voltage and current double closed loop control, the isolation stage uses the open loop control directly, and the output stage uses the voltage closed loop control. In order to speed up the dynamic response and be suitable for the situations where fast dynamic response is required, the predictive direct power control (P-DPC) is applied to the input stage of PET, combined with the space vector pulse width modulation (SVPWM), and the switching frequency can be fixed. After that, the P-DPC control is improved to eliminate the steady-state error and adapt to higher requirements. The simulation models of all levels of PET circuits are established in UlinkMatlab-Sim, and the input stage uses double closed-loop decoupling control and improved predictive direct power control, and the whole PET is simulated under different working conditions. Finally, the hardware and software of PET system are designed and the experimental platform is built. The simulation and experimental results show the advantages of power electronic transformer, the feasibility of applying predictive direct power control strategy to power electronic transformer, and the correctness of other control strategies.
【学位授予单位】：辽宁工程技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM41

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