Enhancing the performance of building integrated photovoltaics

A simulation model for predicting the performance of a solar photovoltaic system with alternating current loads

Observing present scarcity of fossil fuel and emissions of greenhouse gases, electricity generated from Renewable Energy (RE) sources turns out to be the best alternative for generating the power. In RE system, the inverter is normally used to condition the DC power into AC to meet the requirements of load and transmission system. The inverter offers myriad benefits; however, the presence of harmonics (particularly low-order) in the output voltage affects the efficiency and performance of inverter, causes switching losses and decreases the lifetime of the system. In last three decades, significant research has been done to develop the efficient control technique for eliminating the unwanted harmonics. The preliminary review of existing control techniques revealed that the selective harmonic elimination pulse-width modulation (SHEPWM) is more proficient to eliminate the low-order harmonics. However, non-linear transcendental equations used in this technique pose a challenge to solve particularly for calculus-based methods. With the advent of powerful and low-cost computers, bio-inspired intelligent algorithms (BIAs) seem to be a better approach for solving these complex equations. This review paper presents the detailed principle operation of nine well-known BIAs and discusses their application in inverters for harmonic elimination (HE). Moreover, different objective functions are also discussed in this paper which is used by the researchers for HE. Additionally, the performance of five renowned BIAs, namely, Imperialist Competitive Algorithm, Particle Swarm Optimization, Differential Evolution, Bee Algorithm and Genetic Algorithm is critically evaluated. Their performance is analyzed in terms of accuracy, computational complexity, convergence speed, and a number of control parameters. The conclusion has been made on the basis of information extracted from the literature and evaluation results with future recommendations. This single paper covers all the essential information regarding HE in inverters, which will help researchers to design the efficient RE conversion system.

Selective harmonic elimination in inverters using bio-inspired intelligent algorithms for renewable energy conversion applications: A review

For a renewable energy (RE) system, an inverter is normally required to condition the dc power to ac, so that it could be connected to the electrical grid. At the heart of the inverter is the modulation strategy that synthesized the ac waveform by chopping the dc voltage using power electronics switches. Among the numerous modulation techniques, the harmonics elimination PWM (HEPWM) is preferable due to its superior harmonics profile; the elimination of low order harmonics results in reduced switching losses, hence improved inverter efficiency. However, the non-linear and transcendental nature of the HEPWM equations poses a challenge for the conventional computational methods (mostly calculus-based). With the advent of low cost and powerful computers, the soft computing (SC) approach seems to be a better approach and well suited to handle the complexity of the HEPWM problem. This review paper attempts to summarize the operation of the nine SC methods, as well as highlighting their advantages and limitations. Furthermore, the work also presents a critical evaluation on the performance of the three prominent SC techniques, namely, the Genetic Algorithm (GA), Particle Swarm Optimization (PSO) and Differential Evolution (DE). It is envisaged that the information gathered in this single reference will be useful for researchers, designers and practitioners that utilize HEPWM to design energy conversion system.

A review of soft computing methods for harmonics elimination PWM for inverters in renewable energy conversion systems

This study assesses factors that utilities must address when they integrate intermittent renewable technologies into their power-supply systems; it also reviews the literature in this area and has a bibliography containing more than 350 listings. Three topics are covered: (1) interface (hardware and design-related interconnection), (2) operability/stability, and (3) planning. This study finds that several commonly held perceptions regarding integration of intermittent renewable energy technologies are not valid. Among fmdings of the study are the following: (1) hardware and system design advances have eliminated most concerns about interface, (2) cost penalties have not occurred at low to moderate penetration levels (and high levels am feasible); and (3) intermittent renewable energy technologies can have capacity values. Obstacles still interfering with intermittent renewable technologies are also indentified.

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Paul Longrigg

Papers

D.c.-to-a.-c. inverters for photovoltaics

Use of solar photovoltaics to transport and desalt groundwater supplies using brushless D.C. motors