Direct-drive Permanent Magnet Synchronous Wind Power System Optimal Control

Wind energy is a safe non-polluting, renewable energy, and distributed widely in the world, can be large-scale developed, wind power does not depend on fossil fuels, and has a stable cost, in the current national situation, many countries pursuit the sustainable development, and the wind power gets much concern, this leads to the wind power industry developing rapidly. How to reduce the overall cost of wind power system, improve reliability, get better performance and other issues become the focus of people's attention. The traditional system uses asynchronous generator for wind power, not only with low efficiency but also has the gear box, and more than half of the wind power system fault is generated by the gear box. In this paper, for the above problems, we adopt the permanent magnet synchronous motor, and take optimal control studies for direct drive permanent magnet synchronous wind power system.Wind power system energy convertion contains two parts, namely, to convert wind energy into mechanical energy and mechanical energy into electrical energy, the two parts are bounded by the generator, and for the first part of the system, when the wind speed is below rated wind speed, the control objective is the largest capture wind energy, and as capture the degree of wind energy increases, the shock generator system will be greater. According to the frequency separation principle, the wind speed is divided into two parts: high and low frequency parts, low-frequency part adopts the traditional PI control, and for the high-frequency part, according to the LPV to set up the high-frequency LPV model of the wind power system, and design the state feedback gain scheduling controller based on the LPV model, the resulting wind torque can compensate the low-frequency torque effectivly. The experimental results based on dSPACE simulation platform show the effectiveness of the control method to achieve maximum wind energy capture at the same time ensure that the system has less torque shock. For the motion control parts of generator, it needs to track the desired speed to implement the maximum wind energy capture, and we adopt vector control, the traditional vector control needs to install speed sensor, not only increase the moment of inertia, and increase costs, reduce system reliability, so in this paper, we adopt a method based on model reference adaptive sensor-less vector to optimilize the system. The simulink simulation results show that this method can be effective to achieve speed tracking, achieve maximum wind energy capture, improve generator efficiency, while reducing system cost and failure rate.