Dynamic characteristics and regulation strategies of charging process for CAES using two-stage series piston compressors with wind wheel direct drive

Abstract

A dynamic simulation model of a two-stage series piston compressor directly driven by a wind turbine is built up by considering the conservation of mass and energy. The reliability of the piston compressor model is confirmed by comparison with the experimental data. The first and second thermodynamics analyses on the proposed dynamic model are conducted. Analysis results prove that the proposed dynamic model obeys the rules of the first and second laws of thermodynamics in the whole dynamic process. The largest exergy losses are found to be generated in LC and HC. A variable gear ratio regulation strategy is proposed to solve the problem of wind turbine stall. Under the variable back pressure condition and the variable wind speed condition, average wind energy utilization coefficient (Cp) with variable gear ratio regulation is higher than that without regulation by 4.96% and 32.49%, respectively. A variable attack angle regulation strategy is proposed to alleviate the problem of excessive fluctuations in Cp under random wind speed conditions. Average Cp and average power with variable attack angle regulation are higher than those without regulation by 62.55% and 11.81%, respectively. The dynamic simulation results show that the operating characteristics of the charging process under both variable gear ratio regulation and variable attack angle regulation are the best.