Due to the increasingly complexity of the nuclear power device system, the demands for its performance and security become rather high. Once through steam generator (OTSG) has been widely researched and applied because of its practical advantages like simple structure and small volume, good static performance and mobility. It can produce superheated steam, can work without dehumidification device, and can improve the thermal efficiency of a system. However OTSG has evidently shortages on tight coupling, nonlinearity, large hysteresis and strong interference. That makes its controller designing faces with great challenges.
Keeping to the topic of OTSG (Including the feed pump and the feed valve), the main study subjects of this paper are:
Firstly, identifying the plant system and researching the four stages changing of the steam pressure by driving the feed valve with a step signal. Non-minimum phase characteristic is found in the second stage.
Secondly, discussing whether MFAC and PID are applicable to the non-minimum phase characteristic in the second stage of steam pressure changing. Whether they can eliminate the changing in the first stage, overcome the non-minimum phase characteristic, and finally reduce the cyclic stress damage of OTSG.
Thirdly, for the “feed valve-steam pressure” channel, adjusting the feed valve to track the steam pressure. Then, whether the adjusting of the feed valve can resist the disturbance on steam pressure is researched. This research can help us avoid adjusting the circuit and the feed pump frequently and enhances the reliability and security of the system on the premise that no adjust on feed valve and the power of the first circuit.
Compared with the simulation result of PID, the convergence rate of MFAC is evidently faster than PID’s. In brief, MFAC has obvious superiorities in tracking, adapting, anti-interference and overcoming large hysteresis when compared with PID controller.
A Model-Free Stability-Based Adaptive Control Method for Unknown Nonlinear Systems
