Design and Simulation of a New Symmetric/Asymmetric Structure of Multilevel Inverter Based on Switch-Diode-Source Cells

A novel Impedance source seven level Asymmetric Multilevel topology for PV system is presented here. It comprises of a Quasi Z source network and Asymmetric Multilevel Inverter (QZ-AMLI) to synthesize better quality output with low THD. Quasi Z Source Converter (QZSC) with large voltage gain provides a positive boost voltage to an asymmetric multilevel inverter. Asymmetric structure offers large output levels with a smaller number of switches and input sources. QZS network parameters provide a regulated DC supply to the Asymmetric Multilevel inverter (AMLI). DC input magnitude of the inverter is decided by an algorithm. Switching signals are applied in proper sequence to generate required magnitude at the AC output. Regulated DC output voltages of 16V and 32V are obtained at the output of QZSC1 and QZSC2. 7 level inverter output with a magnitude of 48V is obtained by simulation using Matlab /Simulink. The system ensures lower switching losses, reduced gate drive circuitry and improved harmonic profile. Reduced switch and filter requirements lessen the cost of the system.

Download Full-text

Design and implementation of symmetric and asymmetric structure for multilevel inverter

2017 National Power Electronics Conference (NPEC) ◽

10.1109/npec.2017.8310430 ◽

2017 ◽

Cited By ~ 1

Author(s):

Kishor Thakre ◽

Kanungo Barada Mohanty ◽

Ashwini Ku. Nayak ◽

Rabi Narayan Mishra

Keyword(s):

Multilevel Inverter ◽

Asymmetric Structure ◽

Design And Implementation

Download Full-text

Artefact in 20Å-Resolution Electron Images of Negatively Stained Twodimensional Membrane Protein Crystals

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053231 ◽

1982 ◽

Vol 40 ◽

pp. 92-93

Author(s):

Douglas L. Dorset ◽

Barbara Moss

Keyword(s):

Electron Scattering ◽

Cross Correlation ◽

Transmission Function ◽

Group Symmetry ◽

Asymmetric Structure ◽

Object Model ◽

Phase Object ◽

Computing Systems ◽

Resolution Electron ◽

Plane Group

A number of computing systems devoted to the averaging of electron images of two-dimensional macromolecular crystalline arrays have facilitated the visualization of negatively-stained biological structures. Either by simulation of optical filtering techniques or, in more refined treatments, by cross-correlation averaging, an idealized representation of the repeating asymmetric structure unit is constructed, eliminating image distortions due to radiation damage, stain irregularities and, in the latter approach, imperfections and distortions in the unit cell repeat. In these analyses it is generally assumed that the electron scattering from the thin negativelystained object is well-approximated by a phase object model. Even when absorption effects are considered (i.e. “amplitude contrast“), the expansion of the transmission function, q(x,y)=exp (iσɸ (x,y)), does not exceed the first (kinematical) term. Furthermore, in reconstruction of electron images, kinematical phases are applied to diffraction amplitudes and obey the constraints of the plane group symmetry.

Download Full-text

Cell surface changes during aging of human bladder epithelium examined by lectin probes and SEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100162429 ◽

1990 ◽

Vol 48 (3) ◽

pp. 966-967

Author(s):

J. Jacob ◽

M.F.M. Ismail

Keyword(s):

The Elderly ◽

Ultrastructural Changes ◽

Pokeweed Mitogen ◽

Asymmetric Structure ◽

Luminal Surface ◽

Bladder Epithelium ◽

Aldehyde Groups ◽

Cell Surface Changes ◽

Phosphate Buffered Saline ◽

Surface Changes

Ultrastructural changes have been shown to occur in the urinary bladder epithelium (urothelium) during the life span of humans. With increasing age, the luminal surface becomes more flexible and develops simple microvilli-like processes. Furthermore, the specialised asymmetric structure of the luminal plasma membrane is relatively more prominent in the young than in the elderly. The nature of the changes at the luminal surface is now explored by lectin-mediated adsorption visualised by scanning electron microscopy (SEM).Samples of young adult (21-31 y old) and elderly (58-82 y old) urothelia were fixed in buffered 2% glutaraldehyde for 10 m and washed with phosphate buffered saline (PBS) containing Ca++ and Mg++ at room temperature. They were incubated overnight at 4°C in 0.1 M ammonium chloride in PBS to block any remaining aldehyde groups. The samples were then allowed to stand in PBS at 37°C for 2 h before incubation at 37°C for 30 m with lectins. The lectins used were concanavalin A (Con A), wheat germ agglutinin (WGA), phytohaemagglutinin (PHA) and pokeweed mitogen (PWM) at a concentration of 500 mg/ml in PBS at pH 7.A.

Download Full-text