ABSTRACT:
Based on diode-assisted buck-boost inverter, this paper proposes a new commutation torque ripple suppression strategy for brushless DC motor (BLDCM). Four types of switching vectors are constructed, according to the working pattern of the diode-assisted inverter and the operation mode of the BLDCM. Moreover, the effects of switching vector combination on commutation torque ripple suppression and motor speed regulation are analyzed in the commutation and normal conduction periods, respectively. Based on this analysis, the duration of switching vectors within each modulation cycle is derived and the sequence of vectors is arranged at the same time in these two periods. The proposed method can effectively suppress the commutation torque ripple over the full speed range by unified switching vectors during the commutation period, without needing to switch control strategies according to the speed range. In addition, the increase of the voltage stress of switching devices in the inverter bridge can be avoided by designing the duration and sequence of switching vectors during the commutation and normal conduction periods. The effectiveness of the presented method is validated by the experimental results.
KEYWORDS:
1. Brushless DC motor
2. Commutation torque ripple reduction
3. Diode-assisted buck-boost inverter
SOFTWARE: MATLAB/SIMULINK
CONCLUSION:
In this paper, a new commutation torque ripple suppression strategy is proposed based on the diode-assisted boost-buck inverter. This strategy has the following advantages:
1) The proposed method can effectively improve the utilization of DC supply voltage, and it is promising for the industrial applications supplied by low-voltage DC source such as fuel cell, lithium battery, and photovoltaic array.
2) The commutation torque ripple over the full speed range can be suppressed effectively under the proposed method, without needing to switch control strategies according to the speed range.
3) By designing the duration and sequence of the large vector, small vector and zero vector, the increase of the voltage stress of switching devices in the inverter bridge can be avoided during the commutation and normal conduction periods.
4) Compared with the methods of adding a DC-DC converter, the proposed method can reduce the number of switches and passive devices, which is beneficial to reduce the cost of drive system.
REFERENCES:
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