Browsing by Author "Fan, Chia-Juei"

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A Current Index Approach to Compensate Commutation Phase Error for Sensorless Brushless DC Motors With Nonideal Back EMF
(2016-06-01)
Lee, An-Chen
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Wang, Samuel
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Fan, Chia-Juei
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機械工程學系
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Department of Mechanical Engineering
Commutation phase errors during implementation are inevitable in the sensorless drive of the brushless dc (BLDC) motor. This paper analyzed the current waveform during the conducting phase under commutation phase error and nonideal back electromotive force (EMF). The relation between the elapsed time of the commutation phase error with the current waveform, the supplied voltage, and the nonideal back-EMF is derived. Based on this relationship, a reliable optimization method for commutation phase errors compensation is presented. Such method is to minimize the elapsed time of the commutation phase error with robustness properties with respect to parameter variations. In such a way, the peak values of the current at the front and back of the current waveform at each conducting period become more identical, which leads to minimum torque ripple. A digital signal processor-based sensorless BLDC motor controller to implement the proposed method is developed to verify its effectiveness experimentally. Experiment results showed that the proposed sensorless drive is capable of running in different speed and load torque with good performance.
Current Integral Method for Fine Commutation Tuning of Sensorless Brushless DC Motor
(2017-12-01)
Lee, An-Chen
;
Fan, Chia-Juei
;
Chen, Guan-Hong
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機械工程學系
;
Department of Mechanical Engineering
This paper presents a method for fine commutation tuning of brushless direct current (BLDC) motor. First, we analyze the phase current waveform under commutation error and nonideal back-EMF. From the relationship derived, we propose a feedback compensation method in combination with a sensored BLDC motor or any sensorless drive technique to adjust commutation instant by forcing the current integrals of the two half periods in one 60 degrees conducting period to be equal. The method is robust to variations in resistance and inductance, as well as to nonideal back-EMF, pushing the peak values of the current waveform at the front and back of each conducting period to be more identical. Simulations are presented and a digital signal processor (DSP)-based sensorless scheme contingent on a disturbance observer for back electromotive force (back-EMF) estimation in combination with the proposed control method is implemented to verify its effectiveness experimentally. The results show that proposed method is capable of running the motor at different speeds, load torque, and under the speed-varying operating condition with low levels of motor vibration and power consumption.