An efficient experimental method for high power direct drive wind energy conversion systems

Because of energy shortage and environment pollution, the renewable energy, especially wind energy has become more and more considerable all over the world. Direct drive wind energy conversion systems based on multipole permanent magnet synchronous generator (PMSG) have some advantages such as no gearbox, high power density, high precision and easy to control. In our research project, a 2MW direct drive wind energy conversion system is developed. In this paper, an efficient experimental method for high power converter is presented. A large circulating current flows in the converter, but only a small part of the current caused by the losses of the converter flows into the grid. The method can save a lot of energy when the converter is tested and the experiment can be done in the micro grid. The method can test the main stage, drive circuit, protect circuit and some parts of control circuit. Modeling and control scheme of the efficient experimental method are introduced in this paper, as well as the control scheme of the grid side converter. Some differences caused by sinusoidal pulse width modulation (SPWM) and space vector modulation (SVM) in the method have been analyzed. Simulation and experimental results verify the analysis and the conclusion.