Load-following voltage controller design for a static space nuclear power system

The reliability of static space nuclear power systems (SNPSs) could be impr oved through the use of backup devices in addition to shunt regulators, as currently proposed for load following. Shunt regulator failure leading to r eactor shutdown is possible, as is the possible need to deliver somewhat hi gher power level to the load than originally expected. A backup system is p roposed in SNPSs to eliminate the possibility of a single-point failure in the shunt regulators and to increase the overall system power delivery capa bility despite changing mission needs and component characteristics. The ob jective of this paper is to demonstrate the feasibility of such a backup de vice for voltage regulation in static SNPSs that is capable of overcoming s ystem variations resulting from operation at different power levels. A dyna mic compensator is designed using the Linear Quadratic Gaussian with Loop T ransfer Recovery method. The resulting compensators are gain scheduled usin g the SNPS electric power as the scheduling variable, resulting in a nonlin ear compensator. The performance of the gain-scheduled compensator is inves tigated extensively using an SNPS simulator. The simulations demonstrate th e effects of the fuel temperature reactivity coefficient variations on the load-following capabilities of the SNPS, Robustness analysis results demons trate that the proposed controller exhibits significant operational flexibi lity, and it can be considered for long-term space mission requiring signif icant levels of autonomy.