AFRICON 2004

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1. Transient thermal analysis using both lumped-circuit approach and finite element method of a permanent magnet traction motor
2. A doubly-fed induction generator drive for a wind energy conversion system
3. The design of a logical topology for a terabit wide-area optical network in South Africa

Transient thermal analysis using both lumped-circuit approach and finite element method of a permanent magnet traction motor by Y.K. Chin and D.A Staton
Abstract: This paper presents the transient thermal analysis of a permanent magnet (PM) synchronous traction motor. The motor has magnets inset into the surface of the rotor to give a maximum field-weakening range of between 2 and 2.5. Both analytically based lumped circuit and numerical finite element methods have been used to simulate the motor. A comparison of the two methods is made showing the advantages and disadvantages of each. Simulation results are compared with practical measurements.
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A doubly-fed induction generator drive for wind energy conversion system by P.S. Barendse and P. Pillay
Abstract: In recent years, there’s been a renewed interest in renewable energy sources due to the associated environmental problems and eventual shortage of fossil fuels. Wind energy has gained the most interest of all the renewable energy sources due to the progress in wind related technology [1, 2]. The ability of the doubly-fed induction generator (DFIG) to achieve variable speed control with the reduced cost of converter requirements proves to be extremely attractive for the purpose of wind generation [3]. The reduction in cost is achieved through the control of the torque-speed characteristics of the DFIG from the rotor-side. While this system is commercialized, the companies have not published details of the control strategies. This paper provides the necessary background and results to
ll the void between the commercial product produced by a company like Vesta’s, and the literature. The hardware setup, simulated results and experimental results are also presented.
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The design of a logical topology for a terabit wide-area optical network in South Africa by A.D Gazendam, F.W. Leuschner and R. Geldenhuys
Abstract: A novel approach, based on statistical clustering using the Ward linkage as similarity metric, is proposed for designing optical network logical topologies. The geographic distribution of network traffic is taken into consideration, through a modified gravity model that uses regional economic activity to predict network demand. The intra/inter cluster traffic ratio is introduced as a tool for determining the number of hub nodes on the backbone of the multi-level network model. The proposed approach is demonstrated through the design of a logical topology for a hypothetical terabit wide-area optical network in South Africa.
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