Stand-Alone Island Daily Power Management Using a Tidal Turbine Farm and an Ocean Compressed Air Energy Storage System

Due to the high predictability and the high energy density, marine tidal resource has become an area of increasing interest with various academic and industrial projects around the world. In fact, several Marine Current Turbine (MCT) farm projects with multi-megawatt capacity are planned to be installed in the coming years. In this paper, a MCT farm is supposed to be the main energy supply for a stand-alone island. To compensate the MCT farm power variation relating to the tidal phenomenon, an Ocean Compressed Air Energy Storage (OCAES) system is considered to achieve the island power management. The novelty in this work is that conventional Diesel Generators (DGs) would only serve as a backup supply while the main island power supply will be fulfilled by the proposed hybrid MCT/OCAES system. A simplified OCAES model is built-up in this paper with cycle efficiency about 60.6%. Simulations under different working conditions are carried out to validate the feasibility of the hybrid power system. The obtained results show that the proposed system power management can greatly help to decrease DG fossil fuel consumption and CO2 emissio

CAD of a direct drive rotary motor based on giant magnetostrictive alloys

Highly magnetostrictive materials such as Tb-3Dy7Fe2, commercially known as Terfenol-D, have been used to date in a variety of devices such as high power actuators and linear motors. The authors are investigating a finite element model devoted to Computer Aided Design (CAD) of a direct micro-stepping rotary motor. Such a motor would be a high torque micro-radian stepper, capable of precision movements and self-braking in the power off state. The thrust of this paper is to test the validity of the so-called "weak coupling" approach on a motor based on the proven inch worm technique. Comparison between numerical outputs from the model and test results on prototype hardware will be presented

A Simple Fuzzy Logic Approach for Induction Motors Stator Condition Monitoring

Many researches dealt with the problem of induction motors fault detection and diagnosis. The major difficulty is the lack of an accurate model that describes a fault motor. Moreover, experienced engineers are often required to interpret measurement data that are frequently inconclusive. A fuzzy logic approach may help to diagnose induction motor faults. In fact, fuzzy logic is reminiscent of human thinking processes and natural language enabling decisions to be made based on vague information. Therefore, this paper applies fuzzy logic to induction motors fault detection and diagnosis. The motor condition is described using linguistic variables. Fuzzy subsets and the corresponding membership functions describe stator current amplitudes. A knowledge base, comprising rule and data bases, is built to support the fuzzy inference. The induction motor condition is diagnosed using a compositional rule of fuzzy inference

Optimal Design and Energy Management of a Hybrid Power Generation System Based on Wind/Tidal/PV Sources: Case Study for the Ouessant French Island

International audienceHybrid power generation systems have become a focal point to meet requirements of electric power demand. This kind of system combines several technologies and is considered as one of the appropriate options for supplying electricity in remote areas, such islands, where the electric utility is not available. It is one of the promising approaches due to its high flexibility, high reliability, higher efficiency, and lower costs for the same produced energy by traditional resources. Typically, hybrid power generation systems combine two or more conventional and renewable power sources. They will also incorporate a storage system. This chapter will focus on a typical hybrid power generation system using available renewables near the Ouessant French Island: wind energy, marine energy (tidal current), and PV. This hybrid system is intended to satisfy the island load demand. It will therefore explore optimal economical design and optimal power management of such kind of hybrid systems using different approaches: (1) Cascaded computation (linear programming approach); (2) Genetic algorithms-based approach; (3) Particle swarm optimization. In terms of economical optimization, different constraints (objective functions) will be explored for a given 25 years of lifetime; such as minimizing the Total Net Present Cost (TNPC), minimizing the Levelized Cost of Energy (LCE). The concept of reliability will also be explored to evaluate the hybrid system based on renewables to satisfy the island load requirements. In this chapter, the Equivalent Loss Factor (ELF) is considered

Effect of unbalanced voltages on static eccentricity fault diagnosis in induction motors

International audienc

Prediction of Stator Terminal Voltages in IPMSM based on Static and Transient FEM Solution: Trade-off between Accuracy and Speed of Computation

The present work deals with the calculation of the time varying induced emf in permanent magnet synchronous machines from the numerical finite element solution. A review of the existing methods is presented; their intrinsic merits, in terms of accuracy and speed of computation, are compared. The currently used method, which relies on a weighting averaging procedure of the magnetic vector potential (MVP) over the slot area in order to derive the winding flux linkage and the stator induced, has been modified to enhance its accuracy. An alternative method, which relies on the magnetic vector potential distribution along the mid airgap line, is proposed to carry out the same task. This approach has turned out to be very efficient since it enables a straightforward data handling, signal reconstruction, filtering and spectrum analysis of the relevant waveforms to be easily implemented in a single post-processing function. Finally, the relevance and efficiency of each method, in terms of accuracy and speed of computation, has been confirmed by the experimental results

A brief status on condition monitoring and fault diagnosis in wind energy conversion systems

There is a constant need for the reduction of operational and maintenance costs of Wind Energy Conversion Systems (WECSs). The most efficient way of reducing these costs would be to continuously monitor the condition of these systems. This allows for early detection of the degeneration of the generator health, facilitating a proactive response, minimizing downtime, and maximizing productivity. Wind generators are also inaccessible since they are situated on extremely high towers, which are normally 20 m or more in height. There are also plans to increase the number of offshore sites increasing the need for a remote means of WECS monitoring that eliminates some of the difficulties faced due to accessibility problems. Therefore and due to the importance of condition monitoring and fault diagnosis in WECS (blades, drive trains, and generators), and keeping in mind the need for future research, this paper is intended as a brief status describing different types of faults, their generated signatures, and their diagnostic schemes.Wind turbine Induction generator Drive train Condition monitoring Fault diagnosis