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The implementation and experimental verification are described of a simple neuro-controller (SNC) as an excitation controller for a physical model of a single-machine infinite-bus power system. The SNC with one weight, one bias and a linear hard-limit activation function is trained online. A modified error function with additional variables, used for training, ensures good performance and allows additional control functions to be performed. The SNC is used to control the synchronous generator terminal voltage and to function as a power system stabiliser at the same time. The SNC has been implemented using a DSP board mounted on a PC. Its performance has been investigated by experimental tests for various operating conditions and disturbances.

An excitation neuro-controller (ENC) that integrates the automatic voltage regulator (AVR) and the power system stabilizer (PSS) functions using an artificial neural network (ANN) is described in this paper. The input to the controller is the terminal voltage and the output is the field control signal. The PSS action is obtained by using a modified error function that includes speed error and acceleration to update the ENC weights on-line. Simulation studies show that the ENC can provide good dynamic performance for the single-machine infinite-bus system over a wide range of operating conditions.

Using Deep Level Transient Spectroscopy (DLTS), we have investigated the properties of the DX center in GaAsP for the whole range of alloy composition x. We have determined the variation of the defect characteristics (thermal ionization energy Ei, barrier for electron capture B, and energy level location EDX) versus x. From the relationship that exists between Ei, B and EDX, and between B and Δ, the energy difference between the L band and the bottom of the conduction band, we deduce that electron emission and capture occur from and to the DX center via the L band in the same fashion as in GaAlAs alloys. A good fit of the variation of Ei and B versus x is obtained in a model where the DX level is a donor state associated with the L band which is 200 meV deep, like in GaAlAs, as a result of intervalley mixing.