An Adaptive Hybrid Control of Reduced Switch Multilevel Grid Connected Inverter for Weak Grid Applications

作者：Tila Muhammad, Adnan Umar Khan, Yousra Abid, Muhammad Hilal Khan, Nasim Ullah, Vojtěch Blažek, Lukáš Prokop, Stanislav Mišák · 发表于：IEEE Access · 年份：2023 · DOI：10.1109/access.2023.3259323 · 被引用次数：20 · 研究领域：Microgrid Control and Optimization、Multilevel Inverters and Converters、Advanced DC-DC Converters

Grid-connected inverters have a very significant role in the integration of renewable energy resources with utility grids. However, in recent studies, it is revealed that grid-connected inverters are vulnerable to instability when the nature of the grid changes from strong to weak, which produces uncertainty and performance degradation. An increase in grid impedance decreases stability margins, tremendously increases total harmonic distortion after a certain limit, and amplifies the voltage harmonics in the grid. A cascaded reduced switch symmetrical multilevel inverter along with an adaptive hybrid control technique is proposed for injecting power generated from distributed energy resources efficiently and stably to the utility grid. This research contributes twofold: a multilevel inverter topology and the other is its control method. The multilevel inverter reduces total harmonic distortion and size of the filter while increasing power handling capability. The control unit of the proposed system further consists of two parts: one is the synchronous frame current controller, and the other is stationary frame adaptive harmonic compensators. The grid current controller which is working in a synchronous reference frame ensures regulated current injection to the grid. It is not favorable to implement a harmonic compensator in a synchronous reference frame due to computation complexities. Therefore, the stationary reference frame controllers are used for harmonic compensations. B...