Power electronic interface with de-coupled control for wind driven PMSG feeding utility grid and DC load

A wind energy conversion system employing dq control has been proposed for extracting maximum power from a wind-driven permanent magnet synchronous generator (PMSG) and feeding it to a three-phase utility grid. The controller consists of a diode bridge rectifier, a dc–dc boost converter and a voltage source inverter (VSI). The grid synchronisation is achieved by controlling the VSI at the grid side. Besides supplying power to the ac grid, the proposed scheme also feeds a local dc load, as the dc link voltage is maintained constant. To evaluate the performance of proposed scheme, MATLAB/Simulink based model is tested under varying wind speeds. A proportional–integral controller is used for varying the duty ratio of the dc–dc converter to maintain the output dc voltage constant. The decoupled control algorithm for independent control of real and reactive power fed to the grid is implemented using dSPACE DS1103 controller. A steady-state analysis has been developed for predicting the value of duty cycle as well as the reference current for maximum power point tracking at a given wind velocity or rotor speed of PMSG. Experiments have been carried out on a 48 V, 750 W, 500 rpm PMSG and the test results are furnished to validate the developed scheme.