ABSTRACT:
It is a very difficult process to achieve smooth
drivers for the motor operating under variable speed mode. In brushless direct
current motor (BLdc) when back electromotive force waveform is of trapezoidal
type, the developed torque is constant in ideal conditions. However,
practically, torque ripple is present in
the output torque because of the physical design of the motor and its
parameters. Also, the produced ripples are associated with the control and
driver side of the motor. In the previous literature, the drive without a
dc-link capacitor is presented but the torque ripple reduction is not
effective. Hence in another work, the usage of the small capacitor is
recommended and the results are improved. In this work, the quick stabilization
with torque ripple reduction is presented using a bio-inspired algorithm-based
technique in a BLdc motor drive. A Spider based controller is built to generate
the pulse width modulation signals applied to the inverter and the control
signal applied to the capacitor. The effect of utilizing small dc-link
capacitor, on the torque ripple reduction and speed control is investigated.
The performance is also compared with the case of large capacitor utilization
and without a capacitor case. The proposed control strategy is verified
experimentally by implementing with dsPIC30F4011 and the hardware circuit.
KEYWORDS:
1.
Brushless
direct current (BLdc) motor
2.
Dc-link
capacitor
3.
PWM sequence
4.
Spider based
controller
5.
Spider web
construction
SOFTWARE:
MATLAB/SIMULINK
CIRCUIT DIAGRAM:
Fig.
1. Proposed technique for torque ripple compensation.
capacitor.
(c) Im (A) - with small capacitor. (d) Im (A) - with spider.
Fig.
3. Torque comparison. (a) Torque (Nm) - without capacitor. (b) Torque (Nm) - with capacitor. (c) Torque (Nm) - with
small capacitor. (d) Torque (Nm) - with spider.
CONCLUSION:
The
method of designing a three-phase BLdc motor drive by using a single-phase
voltage source is presented with the intention of employing small dc-link
capacitor. In addition, the strategy for reducing torque ripple concern which
is generally presenting in BLdc motor is considered in the work. The
mathematical equations are developed to determine the capacitor rating and the
parameters are set in the simulation to validate the theoretical results. The
utilization of a small dc-link capacitor is evaluated by assessing the torque
compensation waveform and current compensation
waveform with the capacitor-less case and large capacitor case. Besides,
the application of spider web building algorithm in generating the necessary
switching control pulses are observed by comparing waveforms with the
utilization of fuzzy based control algorithm also with the capacitor and without
capacitor case. The utilization of spider web-based control algorithm to
develop the control pulses make the system to
be more stabilized with respect to its speed. Though the scheme has a
switch and a small capacitor as additional components, the total price of the
drive is reduced. Similarly, the control process used for the switches is
simple, extra components are not used. When
the large capacitors are used, the motor reliability is reduced since the large
capacitors are rated for the small period only. In addition, the simulation
results are validated by designing the corresponding hardware using
dsPIC30F4011 and the simulation results are validated.
REFERENCES:
[1]
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[2]
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[3]
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[5]
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