Comparison of sinusoidal excitation and trapezoidal excitation of a brushless permanent magnet motor

The authors compare the performance of a sinusoidal-type, three-phase, twelve-pole, surface magnet motor using sinusoidal excitation and the performance of the same motor using trapezoidal excitation. The comparison is focused on the overall efficiency of the drive for each method. For sinusoidal excitation, the inverter is modulated by a PWM control signal generated by a Motorola 68HC11 microcontroller. A look-up table is used in the generation of the PWM signal. For trapezoidal excitation, the bottom three MOSFETs of the inverter are modulated by a PWM signal generated by hardware.<>