ABSTRACT:
is analyzed theoretically and verified
experimentally. An inverted pulsewidth modulation driving scheme has higher
power efficiency than a conventional six-step driving scheme, particularly
under low rotor speed due to less diode conduction power loss of Sync
metal–oxide–semiconductor field-effect transistors (MOSFETs). However, the
difference in the power efficiency decreases as the rotor speed increases; for
a rotor speed above 1000 r/min, the difference in the power efficiency is
negligible. In addition, the power efficiency of the inverted driving scheme
drops further than one for the conventional six-step driving scheme with
sampling frequency increase. It is due to the additional switching power loss
of Sync MOSFET. The theoretical analysis of power loss in a three-phase
inverter verifies the experimental results.
KEYWORDS:
1.
Brushless
dc (BLDC)
2.
Inverted
pulsewidth modulation (PWM)
3.
Power
efficiency
4.
Power loss
5.
Three-phase
inverter
SOFTWARE: MATLAB/SIMULINK
In this paper, two different driving schemes for a BLDC motor
drive, conventional six-step and inverted PWM, are analyzed in terms of power
efficiency and loss to facilitate the understanding of the type and amount of
the power loss in a three-phase inverter driving BLDC motor. Besides the conduction
and switching power loss of HS and LS MOSFETs, the additional conduction and
switching power loss from Sync MOSFET driven by an inverted PWM driving scheme
must be compared to the conduction power loss from the diode of Sync MOSFET to
select the more power-efficient driving scheme of the two schemes studied. The
power efficiency of the three-phase inverter driven by the inverted PWM driving
scheme is greater than that driven by the conventional six-step driving
scheme, particularly in the low rotor speed range. This is due to the reduction
of the Sync MOSFET diode conduction power loss in the three-phase inverter
driven by the inverted PWM driving scheme.
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