Experimental validation of a proposed single-phase five-level active rectifier operating with model predictive current control

This paper presents a model predictive current control applied to a proposed single-phase five-level active rectifier (FLAR). This current control strategy uses the discrete-time nature of the active rectifier to define its state in each sampling interval. Although the switching frequency is not constant, this current control strategy allows to follow the reference with low total harmonic distortion (THDF). The implementation of the active rectifier that was used to obtain the experimental results is described in detail along the paper, presenting the circuit topology, the principle of operation, the power theory, and the current control strategy. The experimental results confirm the robustness and good performance (with low current THDF and controlled output voltage) of the proposed single-phase FLAR operating with model predictive current control.

A promoção do capital psicológico,work engagement e saúde mental de trabalhadores

Dissertação de Mestrado em Políticas de Desenvolvimento de Recursos Humanos

Age, growth and population dynamics of lemon sole Microstomus kitt (Walbaum 1792) sampled off the West Coast of Ireland

The age, growth, maturity and population dynamics of lemon sole (Microstomus kitt), captured off the west coast of Ireland (ICES division Vllb), were determined for the period November 2000 to February 2002. The maximum age recorded was 14 years. Males of the population were dominated by 4 year olds, while females were dominated by 5 year olds. Females dominated the sex ratio in the overall sample, each month sampled, at each age and from 22cm in total length onwards (when N > 20). Possible reasons for the dominance of females in the sex ratio are discussed. Three models were used to obtain the parameters of the von Bertalanfly growth equation. These were the Ford-Walford plot (Beverton and Holt 1957), the Gulland and Holt plot (1959) and the Rafail (1973) method. Results of the fitted von Bertalanffy growth curves showed that female lemon sole o f f the west coast of Ireland grew faster than males and attained a greater size. Male and female lemon sole mature from 2 years of age onwards. There is evidence in the population o f a smaller asymptotic length (L«, = 34.47cm), faster growth rate (K = 0.1955) and younger age at first maturity, all of which are indicative o f a decrease in population size, when present results are compared to data collected in the same area 22 years earlier. Results of the yield per recruit curve indicate that lemon sole are currently being over-fished o f f the west coast of Ireland. Problems of selectivity within the sampling method, particularly at the discarding stage, may have influenced the outcome of results of the models used in the assessment of this stock. Therefore, additional/future work on this species should include catch data which incorporates discards and not landings data alone.

More letters of Charles Darwin. A record of his work in a series of hitherto unpublished letters, ed. by Francis Darwin ... and A.C. Seward ...

2

More letters of Charles Darwin. A record of his work in a series of hitherto unpublished letters, ed. by Francis Darwin ... and A.C. Seward ...

1

Report of the State board of agriculture on the work of extermination of the gypsy moth.

1898:Jan.

The British Tunicata; an unfinished monograph, by the late Joshua Alder and the late Albany Hancock. Edited by John Hopkinson, with a history of the work by the Rev. A. M. Norman.

1

Scotland illustrated in a series of views taken expressly for this work by Messrs. T. Allom, W. H. Bartlett, and H. M'Culloch. By William Beattie.

2

The British Tunicata; an unfinished monograph, by the late Joshua Alder and the late Albany Hancock. Edited by John Hopkinson, with a history of the work by the Rev. A. M. Norman.

2