1.College of Mechanical and Control Engineering, Guilin University of Technology, Guilin 541004, China;2.School of Electrical Engineering and Automation, Hefei University of Technology, Hefei 230009, China
The renewable energy sources accessed to the power grid through fast-response power converters has received widespread attention, but they often cause frequency stability problems due to the reduction of power system equivalent inertia. This paper analyzes the effectiveness of two existing solutions. The direct differential operation method using phase-locked loop frequency has a slow dynamic response and causes noise amplifications. And the evaluation method of frequency differential signal using the second-order generalized integrator based frequency-locked loop (SOGI-FLL) can avoid the frequency differential operation. Nevertheless, the SOGI-FLL has a limited ability in suppressing the grid voltage disturbances. To solve this problem, this paper proposes a virtual inertia control strategy with the cascaded SOGI-FLL to accurately evaluate the frequency signal. The frequency self-adaptive filter based on SOGI is added to the SOGI-FLL control loop to enhance the disturbance suppression capabilities. Finally, both simulation and experimental platforms of the microgrid with diesel and energy storage system are established, and the simulation and experimental results verify the effectiveness of the proposed control strategy.
This work is supported by Research Startup Fund of Guilin University of Technology (No. GUTQDJJ2019167).
|||SHI Rongliang, ZHANG Lieping, WANG Wencheng, et al. Virtual Inertia Control Strategy Based on Improved Frequency Differential Operation[J]. Automation of Electric Power Systems,2020,44(20):94-102. DOI:10.7500/AEPS20191130001|