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Abstract-This paper focuses on a second order sliding mode based direct power controller (SOSM-DPC) of a three-phase grid-connected voltage source converter (VSC). The proposed control scheme combined with fuzzy logic aims at regulating the DC-link voltage of the converter and precisely tracking arbitrary power references, in order to easily control the system's power factor. Therefore measures are proposed to reduce the chattering effects inherent to sliding-mode control (SMC). Simulations performed under Matlab/Simulink validate the feasibility of the designed Fuzzy-SOSM. Simulation results on a 1kVA gridconnected VSC under normal and faulted grid voltage conditions demonstrate good performance of the proposed control law in terms of robustness, stability and precision.

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The use of the Doubly-fed Induction Generator (DFIG) in large wind turbines is growing rapidly, the wind farms are today required to participate actively in grid operation by an appropriate generation control. The study focuses on the direct power control (DPC) of the DFIG active and reactive powers (DPC) using the so-called sliding mode control (SMC). A model has been developed, including the mechanical, the induction generator and the control parts. The DFIG control strategies and the response of the system during grid disturbances are tested with large grid disturbances due to voltage sags.Keywords-Direct power control, doubly fed induction generator, sliding mode control; variable speed wind energy system.

This paper focuses on wind energy conversion system (WECS) analysis and control for power generation along with problems related to the mitigation of harmonic pollution in the grid using a variable-speed structure control of the doubly fed induction generator (DFIG). A control approach based on the so-called sliding mode control (SMC) that is both efficient and suitable is used for power generation control and harmonic-current compensation. The WECS then behaves as an active power filter (APF). The method aims at improving the overall efficiency, dynamic performance and robustness of the wind power generation system. Simulation results obtained on a 1.5-MW, 690-V, 50-Hz DFIG confirm the effectiveness of the proposed approach.

With the availability of low cost high performance DSP chips characterized by the execution of most instructions in one instruction cycle, complicated control algorithms can be executed with fast speed, making very high sampling rate possible for digitally-controlled inverters. Control methods, which generate the necessary pulse space vector modulation (SVM) have been discussed extensively in literature. These could be classified as voltage controlled and current controlled SVM. All these methods aim at generating inverter output voltage without low-order harmonics. This paper presents theoretical and experimental aspects for DSPbased algorithm to generate space vector modulation (SVM) signals.

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