Electric machines, dynamic models and sensors in drive systems

Abstract

This chapter gives an overview of three widely used machines of the full range of power spectrum. Steady-state torque-speed boundaries in all four quadrants within and above the base speed for the major types of conventional DC and AC machines are introduced first, followed by the dynamic models of these machines. A limited, by no means complete, analysis of the two dominant types of AC machine (the AC induction and the synchronous) dynamics is included with a view to guide the reader to appreciate the necessity for transformations of voltages and currents and flux linkages of a three-phase machine to one of the rotating axes, in order to appreciate how current controls are used for controlling the torque and flux linkages independently of each other. The logical control structures, the RFOC, for these machines then follow for each machine type. This is followed by a brief description of sensor technologies and associated hardware. Finally an overview of recent developments in the AC induction and PM synchronous machines is included.