【摘要】 光伏并网逆变器的直流注入问题会给逆变器本身、电网以及负载造成严重的危害,为此,本文利用重复控制有助于提高补偿精度的特性,提出了一种基于改进重复控制的光伏并网逆变器直流注入抑制策略,能够根据不同保护需求进行补偿策略选择。由于传统重复控制存在动态响应特性差的问题,且光伏并网逆变器输出中的直流分量不是一个恒定不变的常量,因此,本策略以载波周期作为重复控制的补偿周期并对输出直流分量进行计算,将计算结果作为反馈与PI控制一起调整SPWM占空比,实现对光伏并网逆变器直流注入的抑制,大大提高了直流分量补偿的精度和动态响应特性。本文以半波负载为例进行实验,表明了本策略的可行性和有效性,实验以DSC芯片TMS320F28XXX为控制核心。更多还原

【Abstract】 As the DC injection problem of PV grid-connected inverters causes severe harm to inverters themselves, the grid and the load. To this end, this paper proposes a strategy for restraining DC injection of PV grid-connected inverters based on improved repetitive control by utilizing repetitive control’s characteristic of helping increase compensation accuracy, and compensation methods can be selected according to different protection needs. The traditional repetitive control has the problem of poor dynamic response. Besides, the DC component in the output of PV grid-connected inverters is not a constant. Therefore, this strategy employs carrier cycle as compensation cycle of repetitive control and calculates DC component in the output. The calculated results are employed as feedback to adjust SPWM duty cycle with PI control to achieve the restraint of DC injection of PV grid-connected inverters, which greatly enhances compensation accuracy and dynamic response of DC component. The feasibility and effectiveness of this strategy are verified through experimental results by employing half-wave load, and the control core in the experiment is TMS320F28XXX.更多还原