Permanent-magnet brushless DC (BLDC) motors are compact, efficient and mechanically simple, and they are widely used in service robots, personal electric vehicles and multirotor unmanned aerial vehicles. Rotor position is normally obtained from Hall-effect sensors, but these sensors add cost and volume, complicate assembly and alignment, and reduce environmental robustness. Back-EMF sensing is the most mature sensorless alternative, yet its conventional analog implementation requires a low-pass filter and a comparator: the filter attenuates an already weak signal and introduces a phase delay that varies with speed, which is the dominant source of commutation error.......

Keywords: sensorless brushless DC motor; back electromotive force; zero-crossing point detection; terminal voltage sensing.

Due to the differences in computer programs in the methods of calculating them, designing the geometric shapes, and distributing the material in the geometric shapes. We investigated the effect of these differences separately on the results of the calculations of the rate of absorbed dose of gamma rays in this research. The spent fuel assemblies (SFAS) of nuclear fuel acquired from the Serpent program served as the source of gamma-radiation in this investigation. The absorber gamma-dose rate was calculated using a number of methodologies, including the Serpent Monte Carlo method and approximation engineering techniques (BREZ). As a consequence, the possibility of calculating the absorbed dosage of gamma radiation in approximate geometry using engineering programs is studied.

Keywords: Serpent, BREZ, VVER-1200, the absorbed dose rate of gamma radiation, the linear attenuation coefficient.