Variable-Speed-Driven Three-Phase Surface-Mounted Permanent Magnet Synchronous Machine Applied to Wind Generation Systems

Wind generation has been shown to be a suitable alternative source of energy in the context of smart grids. Among the machines used in wind generation systems, the permanent magnet synchronous machine (PMSM) stands out for its high power density, high efficiency, absence of rotor windings, among others. This chapter is dedicated to the study of the variable-speed-driven three-phase surface-mounted permanent magnet synchronous machine (SMPMSM) applied to power generation. The machine model is presented in three-phase, stationary orthogonal \(\alpha \beta \) and synchronous orthogonal dq coordinate systems, as well as the waveforms of the back electromotive force (back-EMF) per phase in each coordinate system. In the case of SMPMSMs with a non-sinusoidal back-EMF waveform, the \(dq_x\) transformation is applied in order to reduce the electromagnetic torque ripple. Based on the machine model in an appropriate reference frame, it is possible to design a decoupled control of torque; as an example, the proportional-integral controller is adopted. In addition, to eliminate the need to use axis angular position sensors or to increase the redundancy, the concepts of rotor position estimation are introduced, and a strategy presented is the use of the Kalman filter together with phase-locked loops. Finally, a study using data from a real machine, employed in wind turbines, exemplifies the concepts covered in this chapter.