PMSG sensorless control with the Derivative-free nonlinear Kalman Filter for Distributed Generation units

A control method for distributed interconnected power generation units is developed. The power system comprises Permanent Magnet Synchronous Generators (PMSGs) which are connected to each other through transformers and tie-lines. A derivative-free nonlinear Kalman Filtering approach is introduced aiming at implementing sensorless control of the distributed power generators. By redesigning the proposed derivative-free nonlinear Kalman Filter as a disturbance observer it is shown that it is possible to estimate at the same time the non-measurable elements of each generator's state vector, the unknown input power (torque) and the disturbance terms induced by interarea oscillations. The efficient real-time estimation of the aggregate disturbance that affects each local generator makes possible to introduce a counter-disturbance control term thus maintaining the power system on its nominal operating conditions.