Research On Power Distribution Control Methods For Space Nuclear Reactor Power Supply

The space nuclear reactor power supply has the characteristics of high power density and long life,so it is one of the ideal energy forms for deep space explorations.The stable power output of the reactor is the premise of ensuring the stable operation of the space nuclear power system.Due to the time-space nature of the core power of space nuclear reactors,the lumped parameter control(LPC)method based on the multipoint dynamic model is not only difficult to describe its distribution characteristics,but also may cause control overflow and observation overflow,which will eventually lead to system instability.Therefore,it is necessary to propose a distributed parameter control method to realize the distributed control of the core power.In this paper,the power distribution control of the space nuclear reactor core power system is studied under the background of the key deployment project of the Chinese Academy of Sciences.Aiming at the problem of the power distribution control of the reactor core,this paper designs corresponding power control strategies for different core structures based on the distributed parameter control(DPC)method.The relevant simulation verification experiments are carried out on the space nuclear reactor simulation platform.The specific research contents are as follows:(1)Firstly,a semi-linear distribution parameter model of the space nuclear reactor core power is established by using a system of semi-linear partial differential equations.Secondly,combined with operator semigroup theory and space differential linear inequality transformation technology,the well-posed problem of the partial differential equation system in this model is analyzed.Finally,the exponential stability of such distributed parameter systems is discussed through Lyapunov theory.(2)A distributed parameter control method based on a finite number of actuators is proposed.Combined with the partial differential equation theory and modeling technology,a feedback control law is designed to achieve exponential stability of the system.The above method is adopted to the reactor core power distribution control of the rotating drum structure.The multi-dimensional simulation shows that the feedback control law can effectively suppress the core axial power peak.(3)Combining the LPC method with DPC method,a Proportional-spatial Differential-based(P-sD)reactor core power distribution control method is proposed.Firstly,the output of the P-sD controller is discretized under the framework of distributed parameter control,and then the displacement tracking subsystem of the multi-node sliding reflector is established.Finally,the subsystem targets the output of the discretized P-sD controller to achieve distributed control of the reactor core power.The simulation results show that the proposed method can effectively suppress the axial power peak of the core and improve the response speed of the system.In conclusion,the distributed parameter control method proposed in this paper can effectively suppress the axial power peak and improve the anti-jamming and load tracking capability of the system.This study plays an important role in promoting the application of DPC method in reactor power distribution control,and provides a theoretical reference for the system design of space nuclear reactors.In addition,the combination of the DPC and LPC method provides a new idea for power distribution control,which has the potential to be applied in other reactor types.