Assessment of Health and Safety Management on Construction Sites in Kenya
Stephen Diang’a1, Wanyona Githae2, Ng’ang’a Kibe3
1Dr. Stephen Diang’a, Academic Professional Qualification, B. ARCH (U.O.N), M. ARCH (U.O.N), PhD ( Kwazul Natal), RSA, Specialization, Construction Project Management, Construction Contract Documentation, Project Risk Management, Architecture, Kenya.
2Dr. Wanyona Githae, Academic Professional Qualification, B.A BLDG ECONS (U.O.N), M. Engineering (Kyoto University, Japan), PhD (UCT), RSA, Kenya.
3Mr. Ng’ang’a Kibe, Academic Professional Qualification, B. PHIL. IN CONSTRUCTION MANAGEMENT (U.O.N); MSC IN Construction Project Management –( On Going) (JKUAT) Specialization, Construction Project Management, Kenya.
Manuscript received on December  14, 2016 . | Revised Manuscript received on December 26, 2016 . | Manuscript published on January 05, 2016 . | PP: 1-3 | Volume-5 Issue-6, January 2016 . | Retrieval Number: F2761015616/2016©BEIESP
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Abstract: In Selective Harmonic Elimination-Pulse Width Modulation (SHE-PWM) technique, optimal switching angles at fundamental switching frequency are computed such that low order harmonics are eliminated, while the fundamental voltage is obtained as desired. The main challenge associated with SHE PWM technique is that a specified number of transcendental nonlinear equations known as Selective Harmonic Elimination (SHE) equations have to be solved to obtain the appropriate switching angles. In this paper, Particle Swarm Optimization (PSO) algorithm with random initial values is proposed for solving SHE equations of an 11-level inverter. The proposed method is derivative-free, accurate and globally convergent. Both computational and MATLAB simulation results show that the proposed method is highly efficient for elimination of the selected low order harmonics as well as minimization of the total harmonic distortion (THD).
Keywords: Multilevel inverter, PSO, modulation index, and harmonics.