Masters Degrees (Centre for Renewable and Sustainable Energy Studies)

Permanent URI for this collection

https://scholar.sun.ac.za/handle/10019.1/314

This collection contains dissertations sponsored by the Centre for Renewable and Sustainable Energy Studies.

Browse

Browsing Masters Degrees (Centre for Renewable and Sustainable Energy Studies) by browse.metadata.advisor "Kamper, M. J."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Design and analysis of a gearless, direct grid, permanent magnet induction wind generator
    (Stellenbosch : University of Stellenbosch, 2011-03) Potgieter, Johannes H. J.; Kamper, M. J.; University of Stellenbosch. Faculty of Engineering. Dept. of Electrical and Electronic Engineering.; Stellenbosch University. Faculty of Engineering. Centre for Renewable and Sustainable Energy Studies
    ENGLISH ABSTRACT: In this study a new type of gearless, direct-drive wind generator, which can be connected directly to the grid, is proposed. The working characteristics of this generator are based upon the principles of the permanent magnet induction generator (PMIG). By omitting the need for a gearbox and power electronic converter this generator type has several advantages regarding cost and reliability. Although the PMIG is proposed in previous studies as favourable for wind power generation, the mechanical complexity and difficult construction associated with these types of generators, seems to be the main reason why these generator systems are not used. The design methods presented in this study are intended to alleviate these constructional issues by proposing the split-PMIG (S-PMIG), where the stator winding and the induction cage-rotor windings are electromagnetically separated. The machine is basically split into two permanent magnet (PM) machines, a grid connected synchronous generator (SG) unit and a turbine connected induction generator (IG) unit. These two units are mechanically linked by a common PM-rotor. To evaluate this concept a finite element (FE) design analysis is done independently for both machine components. The emphasis of the design optimisation is the minimisation of the cogging torque, while still having a decent performing, easily constructible generator. This generator should also have low load ripple content. Cogging torque can result in the failure of the turbine to start up, especially at low wind speeds. As this is a directly grid connected generator, torque ripple transferred to the common PM-rotor can destabilise the generator. Based upon the FE designs a preliminary S-PMIG system is constructed and practically evaluated. Due to the modular nature of the design it is possible to implement the synchronous generator part of the S-PMIG in conjunction with a grid-connected solid state converter (SSC). This allows for a useful comparison with the S-PMIG system. Promising results are obtained from initial tests of the S-PMIG directly connected to the grid. It is shown that the operation of this generator is stable under a wide range of wind load conditions. However, some important machine design issues are identified from these practical results, which could prove vital in the implementation of future S-PMIG designs.
  • Thumbnail Image
    Item
    Design and implementation of a low cost grid-connected 10 kw hydro power system
    (Stellenbosch : University of Stellenbosch, 2010-03) Lombard, Adriaan Cornelius Johannes; Kamper, M. J.; University of Stellenbosch. Faculty of Engineering. Dept. of Electrical and Electronic Engineering.
    ENGLISH ABSTRACT: The world is increasingly being faced with the challenge of effectively exploiting available renewable energy resources, not only to meet an ever growing energy demand, but also to preserve the available amount of fossil fuels and to reduce the amount of carbon dioxide emissions released into the atmosphere by fossil fuelled power stations. Hence, every available renewable energy resource, even small rivers has a contribution to make in the attempt to reduce the amount of fossil fuel generated electricity. The focus of this study is the design and installation of a low cost grid-connected 10 kW micro hydro power system (MHPS). The process to determine the potential of the available water resource is first to be presented. The environmental aspects of these systems, based on the study that is undertaken for the implementation of the landmark example, are discussed. The complete design of a micro hydro power system for a specific site is presented. This design is based on using commercially available components and equipment in an attempt to minimise the total cost of a micro hydro power system. The designed micro hydro power system is installed in-field and the predicted performance of the designed system is verified with measured results of the implemented system. Based on the results of the micro hydro power system landmark example, it is shown through a complete economic study, that this investment is very worthwhile.