Systems aspects of optical technologies for use in datacommunications

This paper reviews the development of system techniques using advanced modulation formats that have arisen in recent years for use in datacommunications. Simulations are provided to allow comparison of the emerging schemes. © 2011 Optical Society of America.

Switching aspects of hybrid semiconductor power devices

A hybrid semiconductor power device has been designed which combines IGBT switching and thyristor on-state characteristics. A single gate signal controls the switching and triggers the transitions between an IGBT and a thyristor mode of operation. This paper discusses aspects of the switching behaviour of this and of similar devices. Simulation results of an example structure are presented and conceivable developments in the switching characteristics of hybrid devices are discussed.

Fault-tolerant aspects of MPC

The architecture of model predictive control (MPC), with its explicit internal model and constrained optimization is presented. Since MPC relies on an explicit internal model, one can imagine dealing with failures by updating the internal model, and letting the on-line optimizer work out how to control the system in its new condition. This aspects rely on assumptions such that the nature of the fault can be located, and the model can be updated automatically. A standard form of MPC, with linear inequality constraints on inputs and outputs, linear internal model, and quadriatic cost function.

Fault-tolerant aspects of MPC

The various aspects of fault-tolerant control systems that have the ability to survive major equipment failures or damages are discussed. Model predictive control (MPC) offers a promising basis for fault-tolerant control. Failures can be dealt with by updating internal models and letting the on-line optimizer control the system in its new condition. Fault detection and isolation (FDI) and the management of complex models are two emerging technologies in this field.

Switching aspects of hybrid semiconductor power devices

A hybrid semiconductor power device has been designed which combines IGBT switching and thyristor on-state characteristics. A single gate signal controls the switching and triggers the transitions between an IGBT and a thyristor mode of operation. This paper discusses aspects of the switching behaviour of this and of similar devices. Simulation results of an example structure are presented and conceivable developments in the switching characteristics of hybrid devices are discussed.

Study of the electric loading aspects of the BDFM using a lumped parameter thermal model

Details of a lumped parameter thermal model for studying thermal aspects of the frame size 180 nested loop rotor BDFM at the University of Cambridge are presented. Predictions of the model are verified against measured end winding and rotor bar temperatures that were measured with the machine excited from a DC source. The model is used to assess the thermal coupling between the stator windings and rotor heating. The thermal coupling between the stator windings is assessed by studying the difference of the steady state temperatures of the two stator end windings for different excitations. The rotor heating is assessed by studying the temperatures of regions of interest for different excitations.