Decomposition and estimation of the pulsed active power of the CPSS in the CFETR tokamak reactor based on the FFT and improved Prony methods

Abstract

The Chinese Fusion Engineering Test Reactor (CFETR) aims to bridge the gap between the International Thermonuclear Experimental Reactor and the demonstration fusion power plant. Its coil power supply system (CPSS) will be connected to an external high-voltage power grid for producing large pulsed active power and reactive power to feed its superconducting coils. To analyze the impact of its active power on the connected high-voltage grid, the active power signal should be modeled initially. Herein, the characteristics of the active power of the CPSS are analyzed by comparing with the pulsed load, photovoltaic power, and wind power. It is modeled as a combination of periodic and decaying components, which are decomposed by the fast Fourier transform (FFT) and improved Prony methods, respectively. The proposed Prony constraint is diagnosed, and the mode size is changed to avoid exceeding the parameters. Both the calculated signal-to-noise ratio and fitting curves show the high accuracy of the proposed estimation procedure. Numerical results show that the number of selected FFT signals has no distinct influence on the estimation accuracy. The optimum Prony mode size of the decaying component estimation may be half the actual signal size when both the computing time and accuracy are considered.