Power Quality Enhancement in Hybrid Photovoltaic-Battery System based on three–Level Inverter associated with DC bus Voltage Control

This modest paper presents a study on the energy quality produced by a hybrid system consisting of a Photovoltaic (PV) power source connected to a battery. A three-level inverter was used in the system studied for the purpose of improving the quality of energy injected into the grid and decreasing the Total Harmonic Distortion (THD). A Maximum Power Point Tracking (MPPT) algorithm based on a Fuzzy Logic Controller (FLC) is used for the purpose of ensuring optimal production of photovoltaic energy. In addition, another FLC controller is used to ensure DC bus stabilization. The considered system was implemented in the Matlab /SimPowerSystems environment. The results show the effectiveness of the proposed inverter at three levels in improving the quality of energy injected from the system into the grid.Peer reviewedFinal Published versio

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

Modulation, efficiency and lifetime of two-level and multilevel converters for a hydropower application

Along with the integration of the renewable energy in the electrical grid, the pumped-storage hydropower has gained more and more attention due to its fast response and energy storage ability. To have a higher overall efficiency and more flexibility of the system, variable speed is preferred in the operation of the pumped-storage hydropower applications. The key component for the variable speed pumped-storage hydropower application is the full-size power converter, which is the main study object in this work.Different converter topologies, such as the two-level converter, the neutral point clamped converter, and the modular multilevel converter, have been investigated in this study. The simulation and experimental results verify the feasibility of the studied modulation and control methods for different converter topologies. The nine-level modular multilevel converter needs four times the amount of the power modules compared with the two-level converter, not to mention the extra submodule capacitors and arm inductors in the nine-level modular multilevel converter. However, the nine-level modular multilevel converter shows the best efficiency of 99.37% at nominal power in the loss study, while the classical two-level converter shows an efficiency of 98.44%. At the end, a lifetime study is conducted for power switches inside a modular multilevel converter, and it is found that with the used semiconductors design, i.e., the semiconductors have an RMS current value that of half of its stated maximum value, the lifetime requirement of 30 years can always be fulfilled

Design and Development of Novel Matrix Converter Performance Enhancement Technique for Induction Motor Drive

Matrix converter is a direct AC-AC converter topology that directly converts energy from an AC source to an AC load without the need of a bulky and limited lifetime energy storage element. Due to the significant advantages offered by matrix converter, such as adjustable power factor, capability of regeneration and high quality sinusoidal input/output waveforms. Matrix converter has been one of the AC–AC topologies that hasreceived extensive research attention for being an alternative to replace traditional AC-DC-AC converters in the variable voltage and variable frequency AC drive applications. In the present paper an indirect space vector modulated matrix converter is proposed. The basic idea of an indirect modulation scheme is to separately apply SVM to the rectification and inversion stages, before combining their switching states to produce the final gating signals. The paper encompasses development of a laboratory prototype of 230V, 250VA three phase to three phase DSP controlled matrix converter fed induction motor drive. The observations and real time testings have been carried out to evaluate and improve the stability of system under various typical abnormal input voltage condition

Wind Farm Grid Integration Architecture using Unified Expandable Power Converter

IEEE This paper proposes a novel unified expandable low switch power electronic converter architecture for grid integration of direct drive variable speed wind turbine (VSWT) system using permanent magnet synchronous generator (PMSG). The proposed unified expandable power converter (UEPC) can interface two or more bidirectional output ports such as wind generators, energy storages and grid. The size of the power converter is compact because of low number of power electronic switches and protection devices and its architecture is easily expandable to accommodate more outputs, i.e., in this case, the wind turbines. A generalized sequential space vector modulation technique is developed based on the operational principle of the proposed converter to control of the outputs autonomously in order to track maximum power point for individual VSWTSs driven PMSG's. It is expected that the proposed approach will reduce the cost of power electronic converters in a wind farm compared to both AC- and DC-link based topologies, which are available for the momen

Development of high speed power thyristor: The gate assisted turn-off thyristor

A high speed power switch with unique turn-off capability was developed. This gate-assisted turn-off thyristor was rated at 609 V and 50 A with turn-off times of 2 microsec. Twenty-two units were delivered for evaluation in a series inverter circuit. In addition, test circuits designed to relate to the series inverter application were built and demonstrated

Power Converter Topologies for Multiphase Drive Applications

The yet growing demand for higher demanding industrial applications and the global concern about harmful emissions in the atmosphere have increased the interest for new developments in electric machines and power converters. To meet these new requirements, multiphase machines have become a very attractive solution, offering potential advantages over three-phase classical solutions. Multiphase machine’s power demand can be split over more than three phases, thus reducing the electric field stress on each winding (protecting the insulation system) and the requirements on maximum power ratings, for semiconductor devices. Moreover, only two degrees of freedom (i.e. two independently controllable currents) are required for independent flux and torque control. Due to the previous facts, the use of multiphase drives has become very attractive for applications and developments in areas such as electric ship propulsion, more-electric aircraft, electric and hybrid electric road vehicles, electric locomotive traction and in renewable electric energy generation. As a consequence of this multiphase drive tendency, the development of power converter topologies, capable of dealing with high power ratings and handling multiphase winding distributions, has encourage the development of new converter topologies, control strategies and mathematical tools, to face this new challenge