Abstract-Clean and sustainable alternative energy is becoming attractive as oil costs rise and the negative side effects of traditional energy systems begin to become apparent. One often overlooked, but still rapidly growing alternative is wave power. There are fascinating new designs for harnessing the tremendous power of the waves. Hence any contribution in this field could be of real interest for numerous specialists. In the paper a novel modular permanent magnet tubular linear generator is proposed and analyzed by means of numeric field computations. It was designed for wave power take off systems to be placed in the Black Sea near the Romanian coasts.

the double excited synchronous machine (DESM) On the speed-torque characteristic two main regions can be which was designed, analyzed and constructed by the authors identified: the constant torque and the constant power region, should offer an improved efficiency while speed is increased respectively; the first one is characterized by a continuously beyond the rated one, and the goal of this paper is to prove it. By increasing speed and power, while the second one, also called using two control techniques, field oriented control (FOC) and the flux-weakening region, is characterized by a hyperbolic direct torque control (DTC) the advantages of the studied the tore whilersped by a quasi prototype are revealed through numerical analysis (by using decreased of the torque while speed increases (a quasi Matlab/Simulink and Flux2D software). Finally, the tests come constant electrical/mechanical power is maintained within the to support the performances obtained by numerical calculation.voltage-current limits). From the control point of view, the strategies that are used Index Terms-field oriented control, direct torque control, nwolagscewreitdudbyBshk[3-FO -rield weakening,numerical nalysis, prototype testing now on large scale were introduced by Blaschke [3] -FOCand Takahashi [4] -DTC. However, not all the advantages of I. INTRODUCTIONthis kind of inverter-machine system have been revealed. A significant efficiency improvement in the constant power Since important improvements have been made regarding speed region (from the torque-speed characteristic) is firstly the control techniques of the special electrical machines, an proved in this work. So, the two aforementioned control adequate operation for any industrial application is obtained strategies are implemented for the validation of their with the appropriate supplying-motor assembly. In the same capability and efficiency. The consideration ( oi the employed time, two of the control techniques, which are widely used in simulations) of the electromagnetic parameters obtained from this industrial environment, are the field oriented and the numerical a lysiso(fin et met es valae diec truecotrltehnqe FO adDT, esetiel) the numerical analysis (finite element method) gives valuable direct torque control technique (FOC and DTC, respectively), conferment and credibility to this study. In our days, the power electronics, as well as the special Another interest of this paper is to demonstrate the electrical machines have become well known study domains, advantages of the proposed solution (the machine supplied In these circumstances, the optimal exploitation of the and controlled by using the aforementioned techniques) for a elements that interact in the converter-machine assembly is given application. Among those applications one can name the target of the researchers. Therefore, the authors are the kinetic energy-recovery in electrical vehicles, by using presenting in this paper the control of a double excited DESM. In this type of applications the speed variation is the ...