This paper proposes an Improved Magnetic Circuit (IMC) model for the optimal design and characteristics evaluation of the Five-Phase Permanent Magnet Synchronous Generator (FP-PMSG) for wind power application. Along with the Finite Element Method (FEM), the IMC model is also preferred for its faster result generation capabilities. The proposed model is used for optimal designing and performance evaluation of FP-PMSG by considering parameters such as leakage fluxes, properties of core material for rotor and stator, properties of rotor permanent magnet sleeve material, effect of saturation and armature reaction. To compute the armature reaction flux, the winding function approach has been opted. Furthermore, extensive analysis is done with respect to different sleeve and core materials along with improvising various dimensional parameters like magnet height, Magnet to Magnet (M-M) gap and sleeve length for high quality performance of FP-PMSG. To validate the results obtained from IMC model and FEM, an experimental prototype is developed and the electromagnetic performances such as generated voltage, Percentage Total Harmonic Distortion (THD) of generated voltage, terminal voltage vs load current, generated Electromotive Force (EMF) vs speed, rectified Direct Current (DC) Voltage vs DC current, output DC Power vs load resistance and percentage (%) efficiency vs current are evaluated. Through fabrication of the prototype of FP-PMSG in the laboratory, a substantial amount of engineering values have been acquired.