Han, "Torque ripple reduction in BLDC torque motor with nonideal back EMF
," IEEE Transactions on Power Electronics, vol.
Stable operation and control of BLDC motor (with trapezoidal back EMF
profile) necessitate the current commutation in windings to be synchronized with instantaneous rotor position.
3) Sensing of the third harmonic of the back EMF
. 4) Detecting the freewheeling diode conduction and related extended strategies.
Klasnic, "Stationary Frame Induction Motor Feed Forward Current Controller With Back EMF
Compensation," Energy Conversion, IEEE Transactions, vol.
During high-speed operations, the Back EMF
(BEMF) produced by the motor must be below the maximum DC voltage of the drive's power bus.
Reed relays contain a reed switch, a coil for creating a magnetic field, an optional diode for handling back EMF
from the coil, and an encapsulating package with connection terminals.
But in low speed region and flux weakening region, the estimated values of the currents and back EMF
cannot help as they have large ripples.
To reduce THD of back EMF
, fractional slot shorted pitch distribution windings are used in [10, 11].
11 gives the calculated back EMF
waveforms (Phase-A) when rotor rotating at 150 rpm, which demonstrated that electric power can be generated by the electromagnetic coupling between the PMs and both windings.
The sensorless motors rely on a controller that will measure the back EMF
from unenergized coils to determine rotor position.
Thus, this algorithm adds sensorless control algorithms based on the observation of back emf