Against the background of clean-energy transition, low-speed wind energy harvesting technology exhibits broad application prospects and serves as an important supplement for new energy utilization, where vortex?induced vibration acts as its core energy-harvesting mechanism. In this paper, a model for calculating the effective energy capture power of the input additional excitation is proposed to explore the effect of the amplitude ratio of the additional excitation on the energy capture mechanism of the rigid flexible coupled wave cone cylinder. The results show that the additional excitation expands the frequency locking range of the wave cone from Ur=6.0~10.8 without additional excitation to Ur=2.4~13.2, which significantly widens the "frequency locking" region of the rigid flexible coupling wave cone, and the maximum amplitude increases to 293.5% compared with that without additional excitation, which improves the energy capture efficiency of the wave cone. When the amplitude ratio of additional excitation increases, the energy capture efficiency increases and the energy value decreases, and the maximum energy capture efficiency increases to 6.08%. The additional excitation can make the vibration of the wave cone concentrated near the additional excitation frequency, and suppress the low-frequency vibration caused by sinusoidal incoming flow, which can greatly improve the amplitude of the wave cone. The research results can provide theoretical support for improving the energy capture efficiency of bladeless wind turbine.