Study of THD in Five Phase PWM Inverter Drive Using Dual Stage Common Mode Filter Using Simulation

A five phase inverter drive is the latest innovative drive, which has the potential to over through the three phase induction motor. Industries will prefer compatible, most reliable converters and inverters in their power systems. To design and construct the power converter or inverters suitable measures have to be considered. One of the main conditions while designing is that generation of minimum Total Harmonic Distortion in any power systems. In order to get the minimum harmonic distortion a Dual stage common mode filter is used in this work. This paper presents the Harmonical comparison between the normal five phase inverter drive with five phase drive with dual-common mode filter using Simulation and results will be presente

Voltage balancing in three-level neutral-point-clamped converters via Luenberger observer

This paper addresses the problems associated with the dc-link capacitor voltages of the three-level neutral-point-clamped power converter: the imbalance of the capacitor voltages as well as the presence of an ac-voltage low-frequency oscillation in the dc link of the converter. In order to cope with them, a mathematical analysis of the capacitor voltage difference dynamics, based on a direct average continuous model, is carried out, considering a singular perturbation approach. The analysis leads to a final expression where a sinusoidal disturbance appears explicitly. Consequently, the two problems can be handled together using the ordinary formulation of a problem of regulating the output of a system subject to sinusoidal disturbances, applying classical control theory to design the controller. In this way, the controller is designed including the disturbance estimate provided by a Luenberger observer to asymptotically cancel the disturbance, while keeping also balanced the capacitor voltages. Experiments for a synchronous three-level neutral-point-clamped converter prototype are carried out to evaluate the performance and usefulness of the converter working as a grid-connected inverter under the proposed control law.MICINN-FEDER DPI2009-09661Junta de Andalucía P07-TIC-0299

Gradient-Based Predictive Pulse Pattern Control with Active Neutral Point Balancing for Three-Level Inverter Medium-Voltage Drives

This paper presents a control method for three-level neutral point clamped (NPC) inverter medium-voltage (MV) drives that addresses the stator current control problem and balancing of the neutral point (NP) potential in a single control loop. To do so, a model predictive control (MPC) algorithm, designed as a multiple-input multiple-output (MIMO) controller, manipulates optimized pulse patterns (OPPs) in real time. As a result, minimal current harmonic distortions are produced, while the NP potential is kept balanced both during steady state and transients. The presented results demonstrate the effectiveness of the proposed control strategy for three-level NPC inverter MV variable speed drive systems.acceptedVersionPeer reviewe

NATURAL VOLTAGE BALANCING IN HYBRID FCC MULTILEVEL CONVERTER

Multilevel converters are frequently used in high and medium power applications. The challenge associated with successful operation of multilevel converters, is the voltage balancing. There are two major techniques dedicated to deal with the voltage balancing, namely: natural and active voltage balancing techniques. Natural balancing is more preferable, since it does not require sensing and in-time controlling equipment. Accepted methods of natural balancing investigation is based on the manipulations of the frequency components. This methods imply heavy computations and not general solutions. In contrast, time-domain analysis, proposed in this paper, produces simple closed-form solutions and requires simple mathematical calculations. The project is focused on performing time-domain analysis in order to investigate natural balancing characteristics of Combined H-Bridge Flying Capacitor Converter (HFCC) converter, for which natural balancing investigations is not reported in literature yet. Modulation strategy was obtained using Matlab software simulation and were implemented with PWM control and Matlab Simulink interface. Obtained results have demonstrated the fast balancing rates with natural balancing, for the majority part of modulation range. In addition, produced analytical equations, that describe voltage balancing dynamics do not require heavy computational effort and could be calculated online

A Fixed Switching Frequency Direct Model Predictive Control for Neutral-Point-Clamped Three-Level Inverters with Induction Machines

This article presents a direct model predictive con-trol (MPC) scheme for drive systems consisting of a three-phase three-level neutral-point-clamped (3L-NPC) inverter and an induction machine (IM). Even though the discussed MPC algorithm is a direct control strategy, it operates the inverter at a fixed switching frequency, while the output harmonic spectrum of the stator current is discrete, with harmonics at non-triplen, odd integer multiples of the fundamental frequency. As a result, the proposed method achieves similar or superior steady-state behavior than that of modulator-based control schemes. Moreover, thanks to its direct control nature, it exhibits the fast transient responses that characterize direct controllers due to the absence of an explicit modulator. Furthermore, the multiple control objectives of the system, i.e., stator current control and neutral point (NP) potential balancing, are addressed in one computational stage, thus avoiding any additional control loops in a cascaded or parallel structure. This favorable control structure is facilitated by the adopted modeling approach, according to which the system behavior is described by the gradient of the system output. In doing so, not only a simple, versatile system model is derived, but also the direct MPC can be formulated as a constrained quadratic program (QP), which can be easily solved in real time with an in-house solver. The effectiveness of the proposed control scheme is experimentally verified on a 4-kW drive system.Peer reviewe

Multilevel Converters: An Enabling Technology for High-Power Applications

| Multilevel converters are considered today as the state-of-the-art power-conversion systems for high-power and power-quality demanding applications. This paper presents a tutorial on this technology, covering the operating principle and the different power circuit topologies, modulation methods, technical issues and industry applications. Special attention is given to established technology already found in industry with more in-depth and self-contained information, while recent advances and state-of-the-art contributions are addressed with useful references. This paper serves as an introduction to the subject for the not-familiarized reader, as well as an update or reference for academics and practicing engineers working in the field of industrial and power electronics.Ministerio de Ciencia y Tecnología DPI2001-3089Ministerio de Eduación y Ciencia d TEC2006-0386

Natural balancing of three-level neutral-point-clamped PWM inverters.

IngenieursweseElektriese En Elektroniese IngeniePlease help us populate SUNScholar with the post print version of this article. It can be e-mailed to: [email protected]

A survey on capacitor voltage control in neutral-point-clamped multilevel converters

Neutral-point-clamped multilevel converters are currently a suitable solution for a wide range of applications. It is well known that the capacitor voltage balance is a major issue for this topology. In this paper, a brief summary of the basic topologies, modulations, and features of neutral-point-clamped multilevel converters is presented, prior to a detailed description and analysis of the capacitor voltage balance behavior. Then, the most relevant methods to manage the capacitor voltage balance are presented and discussed, including operation in the overmodulation region, at low frequency-modulation indexes, with different numbers of AC phases, and with different numbers of levels. Both open- and closed-loop methods are discussed. Some methods based on adding external circuitry are also presented and analyzed. Although the focus of the paper is mainly DC–AC conversion, the techniques for capacitor voltage balance in DC–DC conversion are discussed as well. Finally, the paper concludes with some application examples benefiting from the presented techniques.Peer ReviewedPostprint (published version

Control issues in photovoltaic power converters

2014 - 2015The development of this work was born from cooperation between the Power Electronics and Renewable Sources Laboratory of the University of Salerno and the ABB Solar Group company (ex Power-One) of Terranuova Bracciolini (AR), Italy that is one of the most important manufactures of PV power converters. The aim of this thesis is to investigate control issues in photovoltaic system as the design of PV plants, in the present-day evolving scenario, is not completely defined. This company has pointed out a great interest to explore new control techniques that can have static and dynamic performance better than the existing techniques implemented in its systems, to analyze new scenarios due to the insertion of the Distributed Power Generating Systems (DPGSs) into the grid and to optimize the current methods to extract power from the PV source with the final goal to increase the performance of the PV systems at any level, system, grid and circuit. Hence, the starting points have been highlighted from the industry but they have also a great impact on the scientific and technologic fields. ...[edited by author]XIV n.s