Linear generators are electric machines which generate electrical energy from linear movement. Since these machines can lift gear wheel or power train, they have begun to be used widely nowadays. Since their working areas differ according to speed and power characteristic, this study contains design and optimization of tubular linear generator for free piston practices. The design performed response surface optimization through design variables was acquired as a result of sizing via interface. The association between the determined design variables and the sizes of generator output was examined. In addition, these sizes were used for objective functions of increasing efficiency, decreasing overall volume and increasing general performance and their optimum values were found by using Multi-Objective Genetic Algorithm. Initial and optimum design data were compared with Ansys Maxwell 2D. With overall performance increase, 22,78% decrease was seen in total mass, while 11,7% decrease was seen in cost. In addition, prototype linear generator was made in line with initial geometry data and it was applied with crank slider mechanism.

In this study, an energy harvester using the mechanical vibrations created by the airflow on piezoelectric transducers outside a vehicle was designed, produced and introduced. The introduced harvester has an energy production potential of μJ level. Given an energy power, very little power but long-term harvest was achieved. While the introduced vehicle was driven at speeds of 70, 90, and 110 km/h, energy production at location angles of 0 , 45 , and 90 was determined for each speed. Vehicle speed, location angle, airflow outside the vehicle, and harvester output were measured. Output voltage of the harvester was found to be directly proportional to vehicle speed. Output of the transducers was combined using a circuit topology that would maximize the output voltage. Thanks to this circuit highest output voltage was obtained from the location angle of 0. Thus, maximum output power was obtained at a speed of 110 km/h for 0 location angle. This research develops a new design method for efficient and practical energy generated by piezoelectric sensors placed on a vehicle from the vibration of the airflow around a moving vehicle. This energy harvester can meet the internal micro energy needs of the vehicle with an external battery.

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Abstract:In this paper, general information on the construction of tubular generators are given. Also, the numeric analyses were conducted by using 2D and 3D finite elements software. The output power, iron loss and cogging force change were compared by sensing the primary and secondary structural geometry of generator. Instead of the annular magnets, the magnets in the form of block were used mobile (secondary) part of generator. Also, analyses were conducted on the generator for two primary geometries.

In this study, a medium frequency power transformer has been designed analytically and its sizes have been obtained. The transformer’s analyses were made numerically by 2D AnsysMaxwell Solver software package. The Solver has also helped to study suitable transformer core and winding samples. Unlike medium frequency transformer, which is generally driven by unipolar PWM method, the designed transformer is driven by bipolar PWM method in the study. The core losses were obtained for different core materials (Trafoperm N3 and Amorfous 2605SA1) by AnsysMaxwell numerical and analytical calculations. The calculated losses for no-load working conditions were compared with each other. The designed transformer has been analyzed for its noload and loaded working conditions magnetically. Finally, the radial and axial forces created in the windings have also been examined for loaded working condition.