This paper proposes a model predictive direct current control (MPDCC) method for low switching frequency control of induction motors fed by a neutral point clamped (NPC) three-level inverter. Based on a discrete-time internal predictive model of the drives, the controller predicts future trajectories of stator current
for each admissible switching position, extrapolates the output trajectories and selects the optimal switch vector according to a receding horizon policy of the cost function that evaluates the average switching frequency of inverter. This makes the switching frequency minimized and the predicted current trajectories within its specified hysteresis bounds. Compared with the established one-step predictive current control, the proposed scheme can reduce switching frequency significantly, and keeps similar harmonic characteristics. Simulation results show that the switching frequency of the three-level inverter can be dropped below 500 Hz. A low harmonic distortion rate of three-phase current is achieved, and fast transient response can be realized by using the proposed scheme.
SONG Wen-xiang, RUAN Zhi-yong, ZHU Hong-zhi, ZHOU Jie
. Model Predictive Direct Current Control of Induction Motor at Low Switching Frequency[J]. Journal of Shanghai University, 2013
, 19(6)
: 647
-653
.
DOI: 10.3969/j.issn.1007-2861.2013.06.018
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