Sinusoidal Versus Square-Wave Current Supply of PM Brushless DC Drives: A Convenience Analysis

Abstract

Permanent-magnet (PM) brushless direct current (BLDC) drives are utilized in a variety of applications because of their inherent features and would be even more utilized if their torque performance could be improved. Indeed, when supplied with square-wave currents, the torque-speed characteristic undergoes a drop at high speeds, and a significant torque ripple arises at both low and high speeds due to the commutation phenomena. In this paper, the sinusoidal current supply of the PM BLDC motors is investigated in depth, and an analytical formulation of the torque-speed characteristic, the torque ripple, and the base speed for such a supply are found. Based on the resulting equations, a thorough convenience analysis of the sinusoidal current supply is carried out with respect to the square-wave current in the presence of the commutation phenomena, which is hereafter termed as the real square-wave current supply. Simulation and experimental tests for a study case are given to corroborate the theoretical results. Generation of the sinusoidal current references using Hall sensors is also discussed

A New Approach of Minimizing Commutation Torque Ripple for BLDCM

“…The work in [10] minimizes the torque ripple by selective elimination of torque harmonics achieved through the supply of the motor phases with a sinusoidal-like current waveform. The sinusoidal current supply outperforms the real squarewave current supply over almost the speed range [11]. Summarizing the above studies, it can be concluded that the overlap commutation and conduction modes combination will extend commutation time, increase switching losses, and decrease efficiency [4].…”

“…The main studies on reducing the commutation torque ripple include overlap commutation, two-phase and three-phase conduction modes combination, adding power supply circuits in front of the three phase inverter, modifying power topology, decoupling control, and the sinusoidal current supply [2][3][4][5][6][7][8][9][10][11]. Overlapping commutation and duty pulse width modulation (PWM) optimization are adopted to reduce the torque ripple in [2].…”

“…However, the characters of the trapezoidal phase back-EMFs may not be reflected in the decoupling control, because the complex process of decoupling for high order harmonics is usually neglected. It is worth mentioning that the harmonic components of the back-EMF, apart from being the fundamental component, do not give any contribution to the active electric power when the current is sinusoidal but just determine the torque ripple of the BLDCM [11].…”

Parabola‐trapezoid and staircase current supply methods for PMBLM with full inverter utility and reduced torque ripple

“…And the sinusoidal-wave current is always used to drive the sinusoidal back-EMF motor, which is called as PM BLACM in general [17][18][19][20]. These two current waveforms and their improvements have been used for several different motors [21][22][23][24][25][26][27][28]. In [21], a third-harmonic was injected into the sinusoidal-wave current for dual three-phase permanent magnet machines to improve the output torque.…”

Fault-tolerant of Hall-effect sensors in permanent magnet in-wheel motor drives

“…Permanent Magnet In-wheel Motor (PMIM) fed by sinusoidal-current requires rotor position information with highresolution from Hall-effect sensors. High-resolution position and velocity estimation of PMIM with Hall-effect sensors and its low-cost vector control drives have been a heated discussion in the research area in recent years [3,4,5]. However, in most proposed methods, the fault states of the Hall-effect sensors signals are seldom considered, and few research studies on fault diagnostic and compensations methods are able to overcome the failures of Hall-effect sensors.…”