Dynamic characteristics and flexible control of the coal-fired power plant integrated with molten salt thermal storage system

High penetration of renewable energy imposes stricter flexibility requirements on coal-fired power plants (CFPPs). However, existing research remains insufficient in the dynamic modeling and control strategy design for integrated CFPP-steam generation system (SGS) systems, particularly in enhancing the system's load-ramping rate. This study develops a control-oriented six-input six-output CFPP-SGS dynamic model in MATLAB, systematically capturing the key thermodynamic couplings among the boiler, turbine, and SGS. Then, based on the concept of load decomposition, a flexible multi-source thermal peak shaving control strategy is developed. With the support of a triangular-pulse SGS heat release, a dual-layer coordination mechanism is formed: direct control via the main steam valve and indirect adjustment via the supplementary steam valve. This arrangement significantly improves the system's load-response speed. Simulation results show that when the CFPP and SGS each handle 3% Pe/min load commands, the system achieves an extreme load-ramping rate of 4.22% Pe/min. When each handles 2.5% Pe/min, the ramp rate reaches 3.98%Pe/min, 32.2% higher than the original unit without SGS support, while key parameters such as main steam pressure, intermediate temperature, and evaporator water level remain stable. Disturbance tests show that under low-load conditions, the system exhibits stronger robustness against feed-coal rate and intermediate-point temperature disturbances, whereas under high-load conditions, the suppression of feed-water and intermediate-point temperature disturbances is optimal. The proposed control strategy fully leverages the transient power support of SGS, enabling efficient peak shaving in CFPP-SGS systems.