ABSTRACT:
This
paper presents a new power converter topology to suppress the torque ripple due
to the phase current commutation of a brushless DC motor (BLDCM) drive system.
A combination of a 3-level diode clamped multilevel inverter (3-level DCMLI), a
modified single-ended primary-inductor converter (SEPIC), and a dc-bus voltage
selector circuit are employed in the proposed torque ripple suppression
circuit. For efficient suppression of torque pulsation, the dc-bus voltage
selector circuit is used to apply the regulated dc-bus voltage from the
modified SEPIC converter during the commutation interval. In order to further
mitigate the torque ripple pulsation, the 3-level DCMLI is used in the proposed
circuit. Finally, simulation and experimental results show that the proposed
topology is an attractive option to reduce the commutation torque ripple
significantly at low and high speed applications.
KEYWORDS:
1.
Brushless
direct current motor (BLDCM)
2.
Dc-bus voltage control
3.
Modified single-ended primary-inductor
converter
4.
3-level diode clamped multilevel inverter
(3-level DCMLI)
5.
Torque ripple
SOFTWARE: MATLAB/SIMULINK
Fig.
1. Proposed converter topology with a dc-bus voltage selector circuit for BLDCM
EXPECTED SIMULATION RESULTS:
Fig.
2. Simulated waveforms of phase current and torque at 1000 rpm and 0.825 Nm
with 5 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM
fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter
and a switch selection circuit. (d) BLDCM fed by proposed topology.
Fig.
3. Simulated waveforms of phase current and torque at 6000 rpm and 0.825 Nm
with 5 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM
fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter
and a switch selection circuit. (d) BLDCM fed by proposed topology.
Fig.
4. Simulated waveforms of phase current and torque at 1000 rpm and 0.825 Nm
with 20 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM
fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter
and switch a selection circuit. (d) BLDCM fed by proposed topology.
Fig.
5. Simulated waveforms of phase current and torque at 6000 rpm and 0.825 Nm
with 20 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM
fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter
and a switch selection circuit. (d) BLDCM fed by proposed topology.
Fig.
6. Simulated waveforms of phase current and torque at 1000 rpm and 0.825 Nm
with 80 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM
fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter
and a switch selection circuit. (d) BLDCM fed by proposed topology.
Fig.
7. Simulated waveforms of phase current and torque at 6000 rpm and 0.825 Nm
with 80 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM
fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter
and a switch selection circuit. (d) BLDCM fed by proposed topology.
CONCLUSION:
In this paper, a commutation torque
ripple reduction circuit has been proposed using 3-level DCMLI with modified
SEPIC converter and a dc-bus voltage selector circuit. A laboratory-built drive
system has been tested to verify the proposed converter topology. The suggested
dc-bus voltage control strategy is more effective in torque ripple reduction in
the commutation interval. The proposed topology accomplishes the successful
reduction of torque ripple in the commutation period and experimental results
are presented to compare the performance of the proposed control technique with
the conventional 2-level inverter, 3-level DCMLI, 2-level inverter with SEPIC
converter and the switch selection circuit-fed BLDCM. In order to obtain
significant torque ripple suppression, quietness and higher efficiency, 3-level
DCMLI with modified SEPIC converter and the voltage selector circuit is a most
suitable choice to obtain high-performance operation of BLDCM. The proposed
topology may be used for the torque ripple suppression of BLDCM with the very
low stator winding inductance.
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