Inductances of cageless reluctance-synchronous machines having nonsinusoidal space distributions

A method for the analysis of a cageless reluctance-synchronous machine with nonsinusoidal space distributions is described. First, general equations for inductances are derived from the winding and permeance distributions in the air gap, which are assumed to have space harmonics. It is shown how the amplitude of ascending order decreases more rapidly for the inductance harmonic than for the harmonic of the permanence or the magnetomotive force. Second, the fundamental components of the inductances that vary with the angular position of the rotor are found to be influenced by the space harmonics. Thus, the variations of the self-inductance and mutual inductance are assumed to be purely sinusoidal with no harmonics. On the basis of this mathematical model, simple equations are derived for the general direct and quadrature-axis inductances. Finally, these equations are used in the single-phase standstill method for measuring the parameters of a 1.3 kW test machine, and it is shown that the measured values agree fairly well with the equations.<>