This paper presents a complete approach for switched reluctance generator (SRG) in variable wind energy conversion systems. Two forms of direct power control (DPC) and a commutative system that allows SRG performance at a wide range of speed variations are proposed. Thus, more mechanical energy can be captured in wind generation. In the proposed structure, the SRG operates in a self-excited mode using a common dc bus system of a voltage source inverter connected to an electrical grid. DPCs are proposed by hysteresis of the SRG phase current for low-speed operation (DPC-LS) and by a single pulse of current for high-speed operation (DPC-HS). The low-pass filter employed to obtain the average power generated may slow down the response of the control system of the DPC applied to SRG. To improve the system performance, sliding mode controllers in DPCs were used. For operation throughout a wide speed range, the DPC-LS and DPC-HS controls should be joined. Therefore, a commutative system with smooth transition between DPC modes is proposed. Finally, simulations and experimental tests were conducted to verify the behavior of the proposed arrangement. The results confirmed correct operation of the proposed system.

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Two strategies for wind power systems that simultaneously adjust the powers generation from doubly fed induction generator and achieves grid currents harmonic filtering are presented in this paper. The harmonic mitigation function is developed by algorithms proposed for compensating harmonics from the grid side converter. The quality of power is substantially enhanced. The generator side converter regulates the active and reactive powers that are supplied to the electric grid by the stator flux oriented control. This paper presents a novel control system for power generation and electric grid harmonic compensation, which is described and validated through comparison with other strategies. A harmonic filtering behavior analysis for some operation points using the novel strategy is presented. The proposed system efficiency is verified through simulation and experimental results. The grid current THD when none of the proposed strategies are applied is 17.21%. The THD is reduced to 5.68% when strategy 1 is applied. When strategy 2 is used the THD is decreased to 3.18%.INDEX TERMS Controllers design, doubly fed induction generator, integrated active filter, harmonic filtering, power quality, wind power generation.