Optimal control studies

Abstract

The paper describes work done in examining a particular problem of boiler control. The overall approach is the consideration of the boiler as a unit in the frequency control of an electrical power system.The possibilities of including frequency control within the economic scheduling program are limited by the ability of the individual set to follow large amplitude load demands fast. This limitation is real and has arisen due to the previous empirical methods of control system design for this system. The scope of the problem outlined demands a broad approach.One section describes the derivation of a large analytic non-linear computer model of a natural circulation, non-reheat, boiler. Conclusions are drawn as to the relative importance of various factors, design parameters and existing controls, to the dynamic characteristics of this system.From these results, an even simpler model structure can be derived. A deterministic criterion, reflecting, for a single set, the regulating requirement of the system is desired and the resulting variational problem in two controls and two state variables is solved.Similarly a one control problem is solved and by programming the open loop “optimal” control strategy, as input to the large analytic computer model, the effects of model simplification are demonstrated.