A thermodynamic approach to electromechanical energy conversion. The two-phase asynchronous machine

The aim of the paper is to present a thermodynamic view of the electromechanical energy conversion process. The methodology is illustrated by developing an innovative analysis of a common two-phase asynchronous machine but the method, by way of its very nature, is general and can be applied, in a systematic way, to the analysis of any other transducer, measurement or conversion device, both magnetic and dielectric. The thermodynamic analysis of the two-phase asynchronous machine is developed both at impressed voltages (i.e., at impressed flux linkages), by means of the magnetic energy, and at impressed currents, by means of the thermodynamic potential obtained by the Legendre transformation of the energy. From these thermodynamic properties, the authors obtain the state equations and the electromagnetic torque. Furthermore, the area of the working cycles, i.e., the converted work at the terminals of each winding is evaluated. The active and the reactive power is evaluated and the thermodynamic efficiency of the cyclic conversion process is discussed