Synchronous Machines

Abstract

This chapter considers two types of synchronous machines, the permanent magnet synchronous machine and the synchronous generator. The majority of the electric power is generated by synchronous generators, that is, synchronous machines driven either by hydroturbines, steam turbines, or combustion engines. The expression for the electromagnetic torque may be obtained from a power balance approach. The electrical characteristics of the rotor may be adequately represented with a field winding and short-circuited damper or amortisseur windings. The synchronous generators in a power system are operating at the same electrical angular velocity. The damper windings provide induction machine torque whenever the rotor electrical angular velocity is above or below synchronous speed. It is instructive to observe the variables of the synchronous machine during dynamic and steady-state operation. For this purpose, the operation of a two-phase synchronous generator is illustrated by computer traces.