High Performance Control of AC Drives with Matlab / Simulink Models

4.1 Introduction

This chapter focuses on vector control of AC machines, particularly IM, PMSM, and DFIG. We consider these machines to be the most interesting for modern electric drives, and so the focus will be on their control and simulation. The control of AC machines can be classified into ‘scalar’ and ‘vector’ controls. Scalar controls are simple to implement and offer good steady-state response; however, the dynamics are slow because the transients are not controlled. To obtain high precision and good dynamics, vector control schemes have been invented for use with closed-loop feedback controls. Thus, this chapter focuses on the ‘vector control’ schemes of AC machines after a brief description of the scalar control method.

Adjustable speed drives offer significant energy savings and fast and precise responses in industrial applications. At the beginning of the 1970s [1–9], the principles of torque and flux control were introduced and called ‘field oriented control’ or ‘vector control’ for squirrel cage induction machines and later for synchronous machines. The vector control idea relies on the control of stator current space vectors in a similar, but more complicated, way to a DC machine. The advancement in adjustable speed AC drives was slow until the 1980s, when the microprocessor revolution made it possible to implement complex control algorithms, which made AC machines the dominating machine in the drives market.

The research on vector control of AC machines is active ...