Optimal and sub-optimal excitation control of a single machine system is investigated. Optimal excitation control is derived by using singular optimal control theory, while sub-optimal control is derived by using function minimisation techniques employing dynamic sensitivity functions. Both bang-bang and continuous feedback controls have been considered. A dual mode control arrangement has been used where the control operates in a bang-bang mode during large disturbances and in a continuous feedback mode during small disturbances. It was found that substantial overall improvements were achieved by the optimal and sub-optimal controls in the generator performance both under small and large disturbances. It was also found that the sub-optimal controls furnished a substantial improvement in transient performance of the system under a wide range of operating conditions and parameters. These conclusions have been confirmed on a practical micromachine system. A sub-optimal control consisting of non-linear functions of state has been investigated. This non-linear feedback control made substantial improvement in the system performance under a large range of operating conditions and parameters.
|Date of Award||1977|