Advancements in Three-Phase Electric Motor Control: The Dual Voltag Motor Controller for Seamless Voltage Switching and Enhanced Efficiency

The primary objective of this research was to create, manufacture, and assess the operational efficiency of a Dual Voltage Motor Controller capable of automatically detecting the source voltage in a three-phase system and regulating the electric motor to function with either 220V or 440V AC. The resulting technology comprises a combination of magnetic contactors and a microcontroller, serving as a switching mechanism that streamlines the reconfiguration of the electric motor's twelve leads in a delta-delta configuration. This research was conducted at Guimaras State University, focusing on the development of a device aimed at eliminating the need for rewiring motor terminals when switching between 220V AC and 440V AC power sources, and vice versa. The device is designed exclusively for operation within a three-phase system and for electric motors utilizing a delta-delta configuration with twelve leads. Upon assessing the results of the technical evaluation, it was evident that the Dual Voltage Motor Controller effectively managed to switch the electric motor between 220V and 440V alternating current. Furthermore, the data revealed that the device allowed the electric motor to operate in both forward and reverse rotations, whether under low or high voltage conditions. By introducing this innovative technology, the research effectively resolved the limitations of existing motor controllers by introducing auto-detection of the source voltage and facilitating the seamless transfer of terminal connections via magnetic contactors. According to the feedback from technical experts, there is potential for expanding the device's applicability beyond delta-delta connected motors to also encompass wye-delta starting and running configurations for three-phase alternating current motors

Analysis and modeling of a modular ISOP Full Bridge based converter with input filter

This work presents a modular architecture based on the input series output parallel (ISOP) connection of Full Bridge Phase Shifted power converters with a common input filter. The modeling of the converter architecture taking into account the effect of the common input filter is the previous step to the controller design in order to ensure a proper regulation of external converter quantities, such as output voltage, and internal quantities, such as input voltages. In this paper a small signal model of an ISOP Full Bridge Phase Shifted converter taking into consideration the input filter is developed. Simulation and experimental results validate the theoretical prediction

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Abstract-PWM inverters are widely used in different power electronics applications. PWM waveforms have a harmonic content which should be filtered, typically based on LC topologies. If a transformer is required, the leakage inductance can be used as a series inductance for the LC filter. This work proposes an easy procedure for the integration of the series inductance for harmonic filtering inside the transformer, while the value of the leakage inductance can be determined by design

Structural characterization of the unligated and choline-bound forms of the major pneumococcal autolysin LytA amidase. Conformational transitions induced by temperature

11 p.-8 fig.-5 tab.The secondary and tertiary structures of the choline-dependent major pneumococcal autolysin LytA amidase and of its COOH-terminal domain, C-LytA, have been investigated by circular dichroism (CD) and Fourier transform infrared (FTIR) spectroscopy. Deconvolution analysis shows that the far-UV CD spectrum of both proteins is governed by chiral contributions, ascribed to aromatic residue clusters contained in the COOH-terminal module. The secondary structure of LytA, determined from the FTIR spectral features of the amide I' band, results in 19% of alpha-helix and tight loops, 47% of beta-sheets, 23% of turns, and 11% of irregular structures. Similar values are obtained for C-LytA. The addition of choline significantly modifies the far- and near-UV CD spectra of LytA and C-LytA. These changes are attributed to alterations in the environment of their aromatic clusters, since the FTIR spectra indicate that the secondary structure is essentially unaffected. CD choline titration curves at different wavelengths show the existence of two types of binding sites/subunit. Data analysis assuming protein dimerization upon saturation of the high affinity sites reveals positive cooperativity between the low affinity sites. Thermal denaturation of both proteins occurs with the formation of unfolding intermediates and the presence of residual secondary structure in the final denatured state. The irreversibility of the thermal denaturation of LytA and C-LytA results from the collapse of the polypeptide chain into intermolecular extended structures. At saturating concentrations, choline prevents the formation of these structures in the isolated COOH-terminal module.This work was supported by Programa General de Conocimiento Grants PB93-0114 and PB93-0115-C02-01.Peer reviewe