Analysis of Electric Machinery and Drive Systems

Paul C. Krause

Preference :

The theory of electromechanical energy conversion allows us to establish expressions for torque in terms of machine electrical variables, generally the currents, and the dis- placement of the mechanical system. This theory, as well as the derivation of equivalent circuit representations of magnetically coupled circuits, is established in this chapter. In Chapter 2, we will discover that some of the inductances of the electric machine are functions of the rotor position. This establishes an awareness of the complexity of these voltage equations and sets the stage for the change of variables (Chapter 3) that reduces the complexity of the voltage equations by eliminating the rotor position-dependent inductances and provides a more direct approach to establishing the expression for torque when we consider the individual electric machines.