Event-Triggering Virtual Inertia Control of PV Systems With Power Reserve
Qiao Peng, Zhongting Tang, Yongheng Yang, Tianqi Liu, Frede Blaabjerg
Abstract
Grid frequency support, e.g., by the virtual inertia control (VIC), of photovoltaic (PV) systems, is more demanded than ever before. To achieve the full-range frequency support (i.e., to tackle the under- or overfrequency issues), the power reserve is necessary for PV systems. Accordingly, a power reserve control (PRC) method based on the maximum power point tracking (MPPT) is adopted in this article, referring to as MPPT-PRC. It measures the real-time maximum available power (MAP) periodically, being independent of physical sensors and burdensome computation. However, the MAP measurement loop inevitably couples with the power reserve loop, which makes the realization of the VIC challenging. Aiming at this issue, an event-triggering strategy is elaborately designed to switch the PV system in-between different operating modes. The strategy is realized by a set of control signals. They are responsible for the detection of frequency incidents, the activation of MPPT, the measurement of MAP, respectively. Consequently, the VIC can be achieved based on the MPPT-PRC without any conflicts or instability. Experimental tests are performed on StarSim real-time hardware-in-the-loop system to validate the proposed MPPT-PRC-based VIC, as well as the coordination of the control loops.