Proposed Rotor Field - Oriented Maximum Power Point Tracking Polices for Permanent Magnet Synchronous Generator - Based Wind Turbine

Abstract

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.