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This article proposes three new maximum power point tracking control schemes for permanent magnet synchronous generators in variable-speed wind energy conversion systems. Unlike previously control methods based on traditional voltage source fed equivalent circuit, a current source fed equivalent circuit is proposed where an efficient maximum power point tracking–based load angle control can simply be achieved. The three new control strategies are based on concurrent load angle control–rotor field–oriented method at desired speeds. Each strategy has its own load angle methodology. The first strategy applies constant flux control technique. The second one is based on keeping constant 90° torque angle (zero d-axis current control) method. Finally, the third strategy presents an optimum maximum power point tracking at unity power factor with achieving the favorite linear relationship between the generator stator current and optimum torque. A unified detailed phasor diagram is provided from which the phasor diagram for any of the aforementioned control techniques is produced. Mathematical analysis and MATLAB Simulink model results are presented for each control pattern. Effective validation for the proposed mathematical models is approved.

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The paper presents a new technique for the steady state performance analysis of the DFIG using Adaptive Neuro-Fuzzy Inference System (ANFIS). First, a mathematical model of DFIG in an appropriate d-q reference frame is established. The effect of the excitation voltage vector on the performance characteristics is illustrated to investigate simulations. A novel approach for the performance analysis of DFIG using ANFIS is employed for fast, accurate, and efficient methodology. The proposed ANFIS model has been trained off-line to predict the effect of excitation voltage magnitude, excitation voltage angle and speed on total output power of DFIG without overheating. The performance of the proposed scheme is investigated at different operating conditions. The simulation study indicates accuracy and effectiveness of the ANFIS based modeling of DFIG.

In this paper, a new concurrent unity power factor and constant stator flux linkage (UPF-CFL) control is presented. The main goal of this technique is to introduce the Permanent Magnet Synchronous Generator (PMSG) as an optimal wind energy transducer. The handled generator load angle and back EMF control achieve the optimum requirements for wind applications namely Maximum Power Point Tracking (MPPT). To do this, both UPF and CFL are integrated into one control methodology to obtain the advantages of each one. While the first well utilizes the apparent power increasing the generator side converter capability, the second protects the generator against magnetic saturation to enable higher speed operation. Mathematical model based on constant current fed equivalent circuit is presented taking the constraints of each individual control algorithm into account. The concurrent performance characteristics are presented and compared with each of concurrent separated algorithm characteristics for assessments. The control technique is implemented and finally, simulation testing is provided for evaluation.

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