Research articles (Dept of Electrical Engineering)

Search within this collection:

Advanced Search

Browse by

By Issue Date
Authors
Titles
Subjects

Recent Submissions

Application of the method of D-partitioning for stability of control systems with variable parameters

Yanev, K.M. (University of Botswana, www.ub.bw, NaN, 2007)

[more]

[less]

Abstract:

By the turn of the century, Botswana will be 34 years old as an independent nation. Reflecting on the past, is a background of tremendous achievements from a socio-economic development perspective. The achievements could not have been possible if it was not for the contribution of the construction industry. The construction industry’s (CI) contribution to socio-economic development may be viewed from many areas, among them, creating employment, wealth and demand for manufactured goods, infrastructure and producing factors of production (e.g. office space, factory shells, roads, etc) for other sectors. However, the relationship between the general economy and the CI has not been established explicitly despite numerous studies. Using Botswana’s CI and the economy, some of the paradigms proposed in previous studies revisited.

URI:

http://hdl.handle.net/10311/1063

Files in this item: 1

Yanev_BJT_2007.pdf (928.5Kb)

Design of automatic power factor control system

Yanev, K.M.; Obok Opok, A.; Litchev, A. (University of Botswana, www.ub.bw, NaN, 2004)

[more]

[less]

Abstract:

Maintenance of the proper power factor is a very important matter for the industry and for the economy of any country. A study of the power factor value for a number of industrial plants in Botswana shows that they operate at power factors lower that the optimal values. If a plant power factor is different from its optimal value, this will cause considerable loses in terms of investments for large power generation and supply equipment and in terms of heat dissipation from the supply lines and other equipment. To improve the power factor and keep it at an optimal value, there are a number of preventative measures, as well as corrective actions that could be implemented. The power factor of a plant changes, depending on the number of electrical units operating at a time. After a full analysis of the power factor issue and its optimal case, are automatic control is designed that may maintain the power factor of a plant within values close to optimal. Similar automatic power factor control system can be introduced for all industrial plants with unsatisfactory power factor throughout the country that can improve considerably the efficiency of power utilization.

URI:

http://hdl.handle.net/10311/1062

Files in this item: 1

Yanev_BJT_2004.pdf (1.049Mb)

An algorithm for the determination of feedback coefficients of a state variable feedback control system

Rao, M.V.C. (University of Botswana, http://www.ub.bw, NaN, 2000)

[more]

[less]

Abstract:

This paper describes a new method of determining the feedback coefficients in a state variable feedback system, given the closed loop transfer function, making use of the transfer function between different and relevant points in the feedback configuration used to realize the desired closed loop transfer function, formulas that can be repetitively used to determine the feedback coefficients are desired. The usefulness and simplicity of these methods are demostrated by illustrative examples where the plant has complex poles, coincident poles and zeros and even when the plant is unstable.

URI:

http://hdl.handle.net/10311/756

Files in this item: 1

Rao_BJT_2000.pdf (976.8Kb)

Analysis of dielectric loaded resonator dual-mode filter

Chuma, J.M. (University of Botswana, NaN, 2006)

[more]

[less]

Abstract:

A dielectric loaded rectangular cavity for the design and realisation of different elliptic function filters topologies is presented. The 3-D Transmission Linee modelling method (TLM) is applied to the analysis of the cavity to obtain the resonant frequencies and couplings between the rectangular cavities. As an application to the analysis, a 4-pole elliptic function filter is designed and measured results presented.

URI:

http://hdl.handle.net/10311/701

Files in this item: 1

Chuma_BJT_2006.pdf (800.6Kb)

Improvement of AC electronmagnet performance

Litchev, A.I.; Yanev, K.M. (University of Botswana, NaN, 1999)

[more]

[less]

Abstract:

Electromagnets are essentials for the operation of relays, contactors and other electromagnetic apparatus and take part in driving control and protective circuits of industrial processes and power systems. Performance of each electromagnet affects the driving time and the stability of operation of such circuits. This paper examines the improvement of the performance of AC electromagnets by using two diodes. The theoritical analysis lead to expressions for calculating the maximum, average and minimum values of coil-currents. Due to the electromagnetic processes in the coil, the current becomes pulsating but unidirectional and better force-gap characteristics are achieved. Consideration are made for reduction of the mass ferromagnetic and copper materials in the electromagnets and for decreasing teh responding time.

URI:

http://hdl.handle.net/10311/683

Files in this item: 1

Litchev_BJT_1999.pdf (924.8Kb)

Research articles (Dept of Electrical Engineering)

Research articles (Dept of Electrical Engineering)

Browse by

Recent Submissions

Search DSpace

Browse

All of DSpace

This Collection

My Account