Synchronous machine wind turbine modelling fidelity

This paper examines prevalent modelling problems for dynamic Permanent Magnet Synchronous Generators (PMSG) coupled to the power network via a back-to-back PWM converter. A control strategy is employed using d-q analysis of both the machine and the grid-side converter, allowing a straight-forward control strategy for regulating machine speed, electromagnetic torque and DC-link voltage. The control strategy is implemented in simulation, together with a linear time-invariant model of the machine and converters. A full switching model is developed for comparison against the linear or averaged model. Reformulating the system equations to increase simulation speed is discussed. Transient test cases are developed to study the performance of the system. The control strategies are shown to be effective as the DC-link voltage is regulated well. In addition, a close correlation is demonstrated in the response characteristics of both linear and switching models. This result allows the use of the less resource-intensive model in studies if harmonics may be neglected, thus significantly improving simulation speed without the loss of accuracy.