The coercivity of permanent magnets is an important factor for the various applications including the electric vehicle motors. Improving the coercivity is highly demanded, however, it is quite
sensitive to the microstructure of the magnet. For understanding the relation between the coercivity and the microstructure, the micromagnetic simulations of the permanent magnets have been studied
extensively. Recently, as improving the computer performance and applying numerical techniques, such as the energy minimization, we can treat a multi–grain permanent magnet model in sub–micrometer
scale. Hence, the effects of the magnetic grain size, the grain orientation and the magnetic properties of the grain boundary have been analyzed by the micromagnetic simulation. In addition, combining
the micromagnetic simulation and the path analysis method make the thermal effect analysis enable. In this paper we summarize the foundation of the micromagnetic simulation for the coercivity analysis
and review the studies on the coercivity analyses of the permanent magnet by using micromagnetic simulations.