Search results for " Inverter"
showing 10 items of 67 documents
Comparative Analysis of Modified Modulation Scheme for Three-phase Voltage fed QZS Inverters
2019
Single-stage converters are one promising solution in different field of applications. In particular, quasi-Z-Source VSI topology structure playsan important role because it presents the same advantages of VSI and qZS converters. In addition, it allows increasing the inverter reliability. Moreover, modulation schemes and control strategy are still being developed. For this reason, aim of this paper is to introduce a modified modulation scheme based on the Maximum Constant Boost Control (MCBC) concept and Switching Frequency Optimal (SFO)as reference signals that represents the novelty issue of this work. The analysis has been carried out by comparing the performance of the converter in term…
Modified Modulation Techniques for Quasi-Z-Source Cascaded H-Bridge Inverters
2018
Quasi-Z-source cascaded H-bridge (q Z S - C H B) inverters are one promising solution for high power photovoltaic (PV) systems. This type of topologies inherits the advantages of cascaded converters (i.e., multilevel outputs) and impedance-source inverters (i.e., high conversion ratios). In addition, it allows increasing the inverter reliability (with high redundancy). However, the modulation and control of qZS-CHB inverters are challenging to a certain extent. Thus, this paper proposes modified modulation techniques to increase the performances of qZS-CHB converters in terms of voltage gains and stresses. The novelty lies in the use of the switching frequency optimal as reference signals i…
Experimental study on B-spline-based modulation schemes applied in multilevel inverters for electric drive applications
2019
This work presents the design, simulation, and experimental validation of new B-Spline-based modulation techniques applied to a Multilevel Power Inverter (MPI), particularly focusing the attention on the harmonic content of the output voltages of the inverter. Simulation and experimental results are proposed and discussed, mainly describing the potential benefits, such as the increase of the multi-level operation of the converter, and drawbacks (low-order harmonics) related to the adoption of B-Spline functions for multilevel inverters applied in the field of electrical drives.
Robust model-following control of parallel UPS single-phase inverters
2008
This paper presents a robust control technique applied to modular uninterruptible power-supply (UPS) inverters operating in parallel. When compared to conventional proportional-integral (PI) control, the proposed technique improves the response of the output voltage to load steps and to high distorted output currents, reducing the distortion of the output voltage. Furthermore, an excellent distribution of currents between modules is achieved, resulting in fine power equalization between the inverters on stream. The crossover frequency of the different loop gains involved is moderate, so that robustness to variations of the operation point and to modeling uncertainties is achieved. A compara…
An Adaptive Robust Predictive Current Control for Three-Phase Grid-Connected Inverters
2011
This paper presents an adaptive robust predictive current control (RPCC) for grid-connected three-phase inverters that exhibit zero steady-state current error. The error correction is achieved by means of an adaptive strategy that works in parallel with the deadbeat algorithm, therefore preserving the typical fast response of the predictive law. The resulting control adapts to any particular L or LCL filter by estimation of the resistive part of the filter. As a variety of the RPCC class of control, it offers the best tradeoff between robustness and speed. © 2009 IEEE.
Analytical Investigation and Control System Set-up of Medium Scale PV Plants for Power Flow Management
2012
In the field of photovoltaic (PV) plants and energy conversion from renewable sources, a large part of the technical literature is more devoted to practical aspects (new solar cells, electrically driven PV panels, safety, reduction of parasitic currents, etc.) than to theoretical investigations. Despite this tendency, this paper presents a mathematical analysis of a medium scale photovoltaic power generation system connected to the distribution network and of its control system. In such a system, the conversion stage is unique due to the absence of a boost chopper. The conducted analysis leads to the interesting conclusion that the inverter used in the plant presents two degrees of freedom,…
Experimental validation of a general model for three phase inverters operating in healthy and faulty modes
2012
The paper presents the experimental verification of a general mathematical model of Voltage Source Inverters (VSI) able to simulate fault conditions and which is also useful for the simulation of fault-tolerant systems for different applications. In general, in the past, the problem of faulty inverters modeling has been addressed specifically by considering faults on the different phases as separate cases. Furthermore, traditional models include only the faulty mode and not the healthy mode, so resulting then not able to predict transient phenomena. The model hereafter presented overcomes this drawback. It was formulated by introducing the concept of “healthy leg binary variables”. Such var…
Decoupled control scheme of the grid-connected split-source inverter for renewable energy sources
2016
Grid-connected power conversion systems for renewable energy sources must fulfill several requirements, including high efficiency, reduced cost and complexity, and, quite often, also boost capabilities from the dc sources to the ac power grid. For such applications, single-stage power converters with boost capabilities offer some potential advantages. Among several proposed options, split-source inverter (SSI) has been recently investigated. This paper proposes a decoupled control scheme for the SSIs, where the common mode term of the ac modulation signals is used to control the dc input current. Thus, the dc input current and ac output current can be controlled independently. The proposed …
Control circuit design of the L-LC resonant inverter for induction heating
2002
In this article, the frequency variation control strategy for an induction heating L-LC resonant inverter is analyzed. The control consists of three loops, which are analyzed and reduced to their corresponding small-signal block diagrams. From these diagrams, the optimal structure of the compensation network and the design boundaries for first order closed-loop response are derived. The special case of phase limitation is analyzed because it is unstable in open-loop operation. Finally the implementation of the control circuit is described and experimental results are shown.
Design considerations for transformerless series resonant inverters for induction heating
2002
The aim of the paper is to present some preliminary ideas in order to overcome the output transformer in series resonant inverters for induction heating applications. By adding a third reactive element to the conventional two element resonant inverter, the output matching transformer can be eliminated, allowing accommodation of the resonant frequency and load with the only drawback being the need for an overdimensioning of the output capacitor bank, and benefiting from inherent short-circuit protection.