Switched Active Power Control of a Grid-Connected Inverter With Reduced RoCoF and Frequency Overshoot

In this article, a switched active power control of the grid-connected inverter is proposed. First, the principle of the proposed control is demonstrated with the phase trajectory analysis. The proposed control allows for direct adjustment of the maximum rate of change of frequency (RoCoF) and frequency overshoot of the inverter, thereby enhancing the frequency stability. Next, the stability of the proposed control is examined using the Lyapunov function. For the active power control loop of the inverter, the proposed control has been proven to ensure global asymptotic stability. Then, the parameters of the proposed control are designed. Due to the clear physical meaning, the proposed control allows for explicit derivation of the relationships among RoCoF, frequency overshoot, response time, and active power overshoot of the inverter. Therefore, the controller parameters can be directly designed using the derived analytical equations, simplifying the application of the proposed control. Finally, the proposed control is clarified through detailed comparisons to highlight its advantages. The proposed control achieves a lower RoCoF and frequency overshoot compared to existing controls while maintaining the same active power overshoot and response time. This is demonstrated through theoretical, simulation, and experimental results.