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Application of power electronics in machine control facilitates emulation of practical wind turbine characteristics using electric machine. In this paper, to test and evaluate the performance of newly developed control schemes for the efficient operation of wind energy conversion system, an in-lab small-scale wind turbine simulator has been developed using a separately excited DC motor coupled to a permanent magnet synchronous generator. Steady state characteristics and dynamic behavior of the practical wind turbine are satisfactorily reproduced by the DC motor. Steady state characteristics like tip speed ratio versus coefficient of power, rotor speed versus turbine output power and dynamic response during furling mechanism at high wind velocities are emulated from the developed wind turbine simulator. The simulator system is tested in response to the wind profile data recorded in the field at the hub height of 18.5 meters. The developed wind turbine simulator can be used to represent wind energy conversion system in the process of the development of in-lab microgrid system.

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This paper presents a new adaptive control scheme for small-scale wind energy conversion systems to extract maximum power from turbulent wind for microgrid systems. To improve the system reliability, the proposed maximum power point tracking algorithm is implemented without using mechanical sensors for the measurement of wind speed and generator speed. These two mechanical quantities are estimated from the measured electrical quantities of the system. During initial stage of execution, the control algorithm runs in system-independent mode and after acquiring system related information, it enters into system-specific mode. Effectiveness of the proposed control scheme is verified through simulation studies.Index Terms-Microgrid, Small-scale wind energy conversion system, Mechanical sensorless MPPT control algorithm.

Abstract-This paper investigates the performance and capacity of space time block coded (STBC) multi-user CDMA system over Rayleigh fading channel condition using multiple transmit antennas. Using simulation and analytical approach, we show that STBC CDMA system has increased performance in cellular networks. We also compare the performance of this system with the typical CDMA system and show that STBC and multiple transmit antennas for multi-user CDMA system provide performance gain without any need of extra processing or bandwidth.