Space-vector based, constant frequency, direct torque control and dead beat stator flux control of AC machines

Author(s):  
A. Tripathi ◽  
A.M. Khambadkone ◽  
S.K. Panda
2013 ◽  
Vol 416-417 ◽  
pp. 480-485
Author(s):  
Wei Zhang ◽  
Ping Zhang ◽  
Xin Hao Zhang ◽  
Xiao Feng Shen

This paper has proposed an efficient direct torque control strategy based on space vector modulation (SVM-DTC) for dual three-phase permanent magnet synchronous motor (DTP-PMSM), which is implemented in a synchronous reference frame aligned with the machine stator flux vector. This strategy adopts the space vector modulation technique to compensate for the stator flux error, and then the continuous smooth response of the vector control and the rapid response of direct torque control are both achieved. Simulation studies of a 3KW DTP-PMSM are carried out. Simulation results show the improvement of the torque response, decrease of the torque ripple, the higher steady performance and better flux waveform.


2013 ◽  
Vol 650 ◽  
pp. 537-542
Author(s):  
Zun Nan Min ◽  
Xiao Feng Zhang ◽  
Ting Jian Zhong

Starting from the space vector equations of induction motor, it is deduced space vector equations of induction motor based on iron loss, and calculated the flux equation of optimal loss in determining the output of the speed and torque. by the optimal flux control, improving direct torque control system, the simulation is verified feasibility.


Electronics ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 820 ◽  
Author(s):  
Ibrahim Mohd Alsofyani ◽  
Kyo-Beum Lee

Constant-frequency torque regulator–based direct torque control (CFTR-DTC) provides an attractive and powerful control strategy for induction and permanent-magnet motors. However, this scheme has two major issues: A sector-flux droop at low speed and poor torque dynamic performance. To improve the performance of this control method, interleaving triangular carriers are used to replace the single carrier in the CFTR controller to increase the duty voltage cycles and reduce the flux droop. However, this method causes an increase in the motor torque ripple. Hence, in this work, different discrete steps when generating the interleaving carriers in CFTR-DTC of an induction machine are compared. The comparison involves the investigation of the torque dynamic performance and torque and stator flux ripples. The effectiveness of the proposed CFTR-DTC with various discrete interleaving-carriers is validated through simulation and experimental results.


Author(s):  
Jian-Ding Tan ◽  
Siaw-Paw Koh ◽  
Sieh-Kiong Tiong ◽  
Kharudin Ali ◽  
Ahmed Abdalla

Over the past few years, multiple types of modifications have been proposed onto the Direct Torque Control (DTC) scheme. Among others is the implementation of Space Vector Modulation (SVM). In this paper, two new control strategies are proposed onto an SVM-DTC. Instead of using PI torque and flux controllers, a fuzzy logic control method is implemented in the proposed modification to achieve a more constant switching frequency while minimizing the torque error. The fuzzy logic controller controls the voltages in direct and quadratic reference frame (Vd, Vq). This approach fully utilizes the switching capability of the inverter and thus improving the overall system performance. To overcome issues in open loop stator flux such as DC drift and saturation, a closed loop estimation method of stator flux is also proposed based on voltage model and low pass filter. The performance of the proposed control strategy is benchmarked with that of a conventional DTC–SVM. Simulations and experiments were carried out and the results show that the proposed method outperforms the conventional DTC-SVM in terms of DC-offset elimination and overall system robustness. <p class="MsoNormal" style="text-align: justify; text-indent: 36.0pt;"><span style="font-size: 9.0pt; font-family: 'Arial','sans-serif'; color: black;" lang="EN-US">Over the past few years, multiple types of modifications have been proposed onto the Direct Torque Control (DTC) scheme. Among others is the implementation of Space Vector Modulation (SVM). In this paper, two new control strategies are proposed onto an SVM-DTC. Instead of using PI torque and flux controllers, a fuzzy logic control method is implemented in the proposed modification to achieve a more constant switching frequency while minimizing the torque error. The fuzzy logic controller controls the voltages in direct and quadratic reference frame (V<sub>d</sub>, V<sub>q</sub>). This approach fully utilizes the switching capability of the inverter and thus improving the overall system performance. To overcome issues in open loop stator flux such as DC drift and saturation, a closed loop estimation method of stator flux is also proposed based on voltage model and low pass filter. The performance of the proposed control strategy is benchmarked with that of a conventional DTC–SVM. Simulations and experiments were carried out and the results show that the proposed method outperforms the conventional DTC-SVM in terms of DC-offset elimination and overall system robustness. </span></p>


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