ABSTRACT:
This paper
demonstrates a method of using a DC-DC boost conversion circuit to suppress the
commutation torque ripple of a brushless DC (BLDC) motor with rectangular flux
distribution. The commutation torque of a BLDC motor is depending on the
commutation transient line current. To calculate the line current accurately,
the phase resistance is taken into account, and the phase currents rising and
falling speed are compared. Furthermore, it is proved that the line current
will maintain constant if the DC voltage is lifted in the commutation period.
The desired voltage is even higher than the supplied DC link voltage, if the
back EMF is higher than two fifths of the input DC voltage. A super-lift
Luo-converter is employed to increase the input voltage. The required waveform of
the transient voltage is accomplished by changing the parameters of the power
DC/DC converter based on the mathematical modeling for the proposed circuit.
And the torque ripple is under control. The control stratagem for the torque ripple
suppression is described in the paper and its reliability is testified by the
simulation and experiment results.
KEYWORDS:
1.
Brushless DC
(BLDC) motor
2.
Torque ripple
3.
Super-lift
Luo-converter
4.
Mathematical
modeling
5.
Commutation current
SOFTWARE:
MATLAB/SIMULINK
CIRCUIT DIAGRAM:
Fig. 1. A typical BLDC drive system.
EXPECTED SIMULATION RESULTS:
Fig.
2. Simulated DC link current of the proposed BLDC drive system.
Fig.
3. Measured DC link current of a typical BLDC drive system.
Fig.
4. Measured DC link current of the proposed BLDC drive system.
REFERENCES:
[1] R Carlson, M Lajoie-Mazenc, J
Fagundes. Analysis of torque ripple due to phase commutation in Brushless DC
machines[J]. IEEE Trans. Ind.Applicat., 1992, 28: 632-638.
[2] Y Murai, Y Kawase, K Ohashi, et al.
Torque ripple improvements for brushless DC miniature motors[J]. IEEE
Transactions on Industry Applications, 1989, 25(3): 441-450.
[3] Liu Yong, Zhu Z Q and David H, “Commutation-Torque-Ripple
Minimization in Direct-Torque-Controlled PM Brushless DC Drives,” IEEE Trans
on Industry Applications, vol.43, pp.1012-1021, July 2007.
[4] Zhang Xiaofeng and Lu Zhengyu, “A
New BLDC Motor Drives Method Based on BUCK Converter for Torque Ripple
Reduction,” IEEE 5th International Conf. on Power Electronics and Motion Control,
vol. 2, pp. 1-4, August 2006.
[5] Ki-Yong Nam, Woo-Taik Lee, Choon-Man
Lee and Jung-Pyo Hong, “Reducing torque ripple of brushless DC motor by varying
input voltage,” IEEE Trans. on Magnetics, vol.42, pp. 1307 – 1310, April
2006.
