Search results for "Inverters"

A Design Methodology for Low-Power MCML Ring Oscillators

2007

In this paper, a low-power design method for MCML based ring oscillators is presented. The proposed method takes into account the parasitic capacitances of the MOS transistors. To validate it, some ring oscillators with different oscillation frequencies were designed in a 0.18 mum CMOS technology. SPICE simulations demonstrate the effectiveness of the design method.

INVERTER-BASED DISTRIBUTED GENERATORS, MODELING AND CONTROL

In the last few years, electrical power generation is moving from a centralized generation towards distributed generation including on-site Renewable Energy Sources (RESs). In order to overcome RES related issues, as intermittent and fluctuating power, storage elements are included in the on-site generation system. The interaction between distributed generator (DG) units including RES, storage and front-end power converters should be carefully modeled in order to analyze the power system stability. An accurate modeling of DGs is required. In this thesis, a new modeling approach has been proposed for the inverter-based DGs based on the concept of electrostatic synchronous machines. Detailed …

Comprehensive Modeling and Experimental Testing of Fault Detection and Management of a Nonredundant Fault-Tolerant VSI

2015

This paper presents an investigation and a comprehensive analysis on fault operations in a conventional three-phase voltage source inverter. After an introductory section dealing with power converter reliability and fault analysis issues in power electronics, a generalized switching function accounting for both healthy and faulty conditions and an easy and feasible method to embed fault diagnosis and reconfiguration within the control algorithm are introduced. The proposed system has simple and compact implementation. Experimental results operating both at open- and closed-loop current control, obtained using a test bench realized using a dSPACE system and the fault-tolerant inverter protot…

Mathematical formulation of pulse amplitude modulation selective harmonic elimination in multilevel three phase inverters

2022

In this paper multilevel cascaded H-bridges (CHB) three phase inverters with 2n dc sources, n=1,2,3,... are considered and a mathematical formulation providing both 2n switching angles and dc voltage source to eliminate n+1 harmonics and their respective multiple from their output voltage waveform, is proposed. The computed angles don't depend on modulation index and the source voltages linearly vary with it. The proposed procedure finds the solution through an analytical formula that avoids to solve transcendental systems and presents very low computational cost. A lot of low order harmonics are eliminated, returning a very low total harmonic distortion (THD). Particularly for 9-level conf…

Reliability Analysis of Three Homogeneous Fault-tolerant Inverter Topologies

2016

Abstract—In this article, non-redundant fault-tolerant inverter topologies are addressed. A novel fault-tolerant control strategy which enhances performances during post-fault operation is proposed. Benefits from the proposed strategy over conventional fault-tolerant topologies are investigated in terms of system reliability. Cost, post-fault performances, and system reliability of the proposed solution are compared with both a conventional triac-based fault-tolerant inverter and a T-type inverter. The reliability analysis of each selected configuration is carried out by means of Markov chains. The analysis is validated through a comparison of reliability and sensitivity curves. As shown by…

Investigation about selective harmonic elimination in unbalanced multilevel inverters

2022

In this paper 5 and 7 levels cascaded H-bridges inverters are considered, feeding by unequal dc voltage sources. The effect of these unbalancing operation is examined concerning harmonic analysis and total harmonic distortion of the output voltages. The system of equations, obtained by the expansion in the Fourier series of phase output voltage, is solved by applying a method of graphic solution that allows obtaining the switching angles able to eliminate the lower order harmonics.

Grid-Following and Grid-Forming MODELS in ATP-EMTP for Power Systems Simulation

2022

The paper presents the models of grid-following and grid-forming converters in the software ATP-EMTP for power systems simulation. The models are developed using the MODELS language, they are described in details discussing all issues and aspects related to the implementation, and they are also shared as open source models. The models are validated with a simulation-based approach, comparing the results with the models developed in MATLAB/Simulink and in NEPLAN, considering both the phasor RMS and EMT time domains, and thus performing a comprehensive cross-platform and cross-domain validation. In line with the spirit of the ATP software and community, the models of grid-following and grid-f…

Decoupled control scheme of grid-connected split-source inverters

2017

Grid-connected power conversion systems for renewable energy sources must fulfill several requirements, e.g., the high efficiency, the reduced cost and complexity, and, quite often, the boost capabilities that is usually achieved using a front-end dc–dc boost converter before the inversion stage, leading to a two-stage architecture. Meanwhile, single-stage power conversion systems, which perform the boosting operation within the inversion one, offer some potential advantages, in terms of reducing the complexity and the volume of the whole system. Among several proposed options, the split-source inverter (SSI) has been recently proposed by Abdelhakim et al. as an alternative option with some…