Title :
Flux-Weakening Characteristics of Trapezoidal Back-EMF Machines in Brushless DC and AC Modes
Author :
Zhu, Z.Q. ; Shen, J.X. ; Howe, D.
Author_Institution :
Dept. of Electron. & Electr. Eng., Univ. of Sheffield
Abstract :
The performance of a brushless motor which has a surface-mounted magnet rotor and a trapezoidal back-emf waveform when it is operated in BLDC and BLAC modes is evaluated, in both constant torque and flux-weakening regions, assuming the same torque, the same peak current, and the same rms current. It is shown that although the motor has an essentially trapezoidal back-emf waveform, the output power and torque when operated in the BLAC mode in the flux-weakening region are significantly higher than that can be achieved when operated in the BLDC mode due to the influence of the winding inductance and back-emf harmonics
Keywords :
brushless DC motors; magnetic flux; torque; back-emf harmonics; brushless AC mode; surface-mounted magnet rotor; torque; trapezoidal brushless DC motor; winding inductance; Brushless motors; Commutation; Educational institutions; Electromagnetic scattering; Electron traps; Magnets; Optimal control; Rotors; Surface waves; Torque control; brushless ac; brushless dc; commutation advance; flux weakening; permanent magnet machine;
Conference_Titel :
Power Electronics and Motion Control Conference, 2006. IPEMC 2006. CES/IEEE 5th International
Conference_Location :
Shanghai
Print_ISBN :
1-4244-0448-7
DOI :
10.1109/IPEMC.2006.4778124
