Comparison of a cascade and feedback linearisation scheme for DC link voltage control in a grid connected wind turbine

This paper compares cascade and feedback linearisation controllers for dc link voltage control of back to back IGBT inverter drives. The cascade controller is implemented using an inner loop controlling i_d and i_q, and an outer loop controlling the link voltage. It is shown that the linear cascade controller will only guarantee the desired closed loop response at a specific operating point. A feedback linearisation controller is then developed then developed. Using this controller results in a stable system across the operating space. The feedback linearisation controller is applied to a variable speed wind turbine model, and satisfactory control of the DC Link voltage is achieved.