Aspects Regarding Electromagnetic Torque of Brushless Direct Current Motors

Interest paid lately to brushless direct current motors made the researches regarding the optimum design and construction of these motors to be very present. The study carried out, by the simulations we presented, shows that these motors have high torque oscillations in a complete rotation. There are identified the slots which create high torques, respectively low torques, in a complete rotation, thus justifying the oscillations. In this paper there is emphasized that the optimum variant of maximum torque involves a supply by six pulses per period in direct direction, also indicating the value of the control angle. The most unfavourable variant occurs at brushless direct current motor supplied by three pulses per period and reverse succession of phases, where the average value of the torque decreases by 56.7% over the optimum machine. An almost constant torque cannot be obtained for brushless direct current motor, but we can draw near this requirement.