It is very important to select proper maximum power point tracking algorithm in order to achieve best performance and low cost for wind turbine–generator combination. A permanent magnet synchronous generator steady-state unity power factor analytical model based on a current source—equivalent circuit is provided. Validation of the identified load angle effect in current source as compared with that of the commonly used voltage source permanent magnet synchronous generator is presented. Then three new maximum power point tracking–load angle control algorithms based on current source model are presented. They all apply magnitude and frequency control techniques for Digital Signal Processor control systems. The first one presents maximum power point tracking–unity power factor applying constrained load angle control algorithm. The merits of the next two developed schemes are quickly and precisely tracking the maximum power output of the wind turbine; thus, the second and third algorithms are then characterized with linear control systems. The linearity of the second scenario is between load angle and reference speed while the third one has a load angle–torque linear relationship which shows its optimality. Finally, the controlled characteristics and implementation for the optimum case are presented for both stationary and synchronous reference frames (for vector control purposes). Simulation modeling for optimum case is provided and its results match well with the proposed predictive control algorithm.

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.

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.