A new simulation model of BLDC motor with real back EMF waveform

A BLDC motor with the characteristics of high speed and high power density has been more widely used in industrial areas. As for the design of the motor drive system, a simulation method has been used for the drive system, and the controller of the BLDC motor has become more complicated and precise. The torque characteristic of a BLDC motor is a very important factor in the design of the motor drive system, so it is necessary to predict the precise value of torque, which is determined by the back EMF waveform. The conventional simulation model of BLDC motor is obtained by approximation of real back EMF waveform to ideal trapezoidal waveform. But as the shapes of slot, skew and magnet of BLDC motor are various subject to design purposes, the real back EMF waveform is to some degree deviant from the ideal trapezoidal waveform. As a result, when using the ideal trapezoidal waveform, the error occurs. As a consequence, in order to lessen such an error, the model of the BLDC motor with a real back EMF waveform is needed instead of its approximation model. In this paper, for the reduction of error in simulation, a new simulation model of the BLDC motor with nearly real back EMF waveform is proposed and through the simulation, the validity of the proposed model is shown for a three-phase BLDC motor