Abstract:

To investigate the operational regulation strategy， complexity， and stability of the expander during the startup process of an advanced adiabatic compressed air energy storage （AA-CAES） system， proportional-integral-derivative （PID） control was implemented on the temperature and pressure parameters at the expander inlet based on the established expander energy release model. The effects of the pressure gain coefficient K and temperature proportional coefficient K_p on the startup characteristics of the expander were systematically analyzed， including the dynamic responses of output power， outlet temperature， and outlet pressure， as well as the stability during the startup process， thereby enhancing the system's anti-interference capability to address sudden failures of key equipment. The results showed that when K=0.5， compared with K=1.5， the output power peak was 4.2% higher， the pressure decline was more gradual， and the curve slope was smaller， exhibiting better response smoothness. When K_p=0.1， the peak expansion ratio was about 0.54% higher than that when K_p=0.5， while the peak isentropic efficiency at different K_p values remained consistent， both reaching 0.88. When K=1.0， the peak outlet temperature was the smallest and the stabilization time was the shortest. When K_p=0.3， the isentropic efficiency could rapidly stabilize. The findings indicate that reasonable regulation of PID parameters can significantly improve the expander startup performance， thereby providing control strategies for solving the problem of unit stability degradation caused by key equipment failures.

Key words: advanced adiabatic compressed air energy storage system, expander energy release, PID control, startup stability, temperature proportional coefficient, pressure gain coefficient