A hybrid flyback LED driver with utility grid and renewable energy interface
In renewable energy sources, the objective is maximum extraction and utilization of the available power. In this paper a hybrid flyback converter with multi ports-an AC Grid, a PV and a DC LED ports — is proposed to be used as an LED driver. The converter has the capability to achieve two objectives: first to maintain a continuous supply to the LED lighting system either from the Photovoltaic (PV) panel or the grid, and second to achieve maximum utilization of the solar PV panel by tracking the maximum power point and exporting surplus power to the grid, or getting the power deficit from the grid. The topology of the converter, operating principle, modes of operation and control structure are presented in this work. The concept of the hybrid flyback converter is verified using Matlab Simulink®. An experimental prototype is developed and tested for a 120-watt system, with 35 VDC solar panels, 120 Vrms 60 Hz grid and 24 VDC LED lights.
Green Communications and Computing Networks
The three articles in this special section focus on the IEEE's Environmental Engineering Initiative (IEEE EEI) that was presented at the United Nations Millennium meeting. To support global environmental sustainability, the IEEE EEI launched a flagship conference, the IEEE International Environmental Engineering Conference, with the first edition located in Milan, Italy, in March 2018, which allowed topics relevant to interactions of various IEEE fields to interact with the scientific and professional communities in other technical areas of environmental engineering,
Pig Vocalizations Under Selected Husbandry Practices
Acoustical characteristics of vocalizations of sows, piglets, and nursery pigs under selected husbandry practices were analyzed with a digital signal processing system. The duration (D) and major energy-resonance frequency (P) for each call were determined as follows: a) processing of piglets (D = 0.81 s and f* = 3 700 Hz); b) food anticipation of breeding-gest ation sows (2.50 s and 3 000 Hz); c) isolation of piglet (0.34 s and 500, 3 500 Hz); d) startling of nursery pigs (0.29 s and 900 Hz); e) sows in heat (3.07 s and 1 375 Hz); f) farrowing (0.10 s and 3 000 Hz); g) sow nursing (0.15 s and 1 000 Hz); and h) mate greeting of sow (0.13 s and 1 000 Hz). Calls a) to d) are responses to human generated stressors, and calls e) through h) responses to social and physiological states of the pigs. Thus, vocalizations can be segmented for different pig production situations.