scholarly journals Improved Close Loop Stator Flux Estimation of Direct Torque Control Drive

2012 ◽  
Vol 38 ◽  
pp. 572-577
Author(s):  
Hassan Farhan Rashag ◽  
S.P. Koh ◽  
Ahmed N. Abdalla ◽  
Nadia M.L. Tan ◽  
K.H. Chong ◽  
...  
Keyword(s):  
Direct Torque Control ◽  
Torque Control ◽  
Flux Estimation ◽  
Stator Flux

Improved Stator Flux Estimation for Direct Torque Control of Induction Motor Drives

2016 ◽  
Vol 7 (4) ◽  
pp. 1049
Author(s):  
Yahya Ahmed Alamri ◽  
Nik Rumzi Nik Idris ◽  
Ibrahim Mohd. Alsofyani ◽  
Tole Sutikno
Keyword(s):  
Induction Motor ◽  
Cutoff Frequency ◽  
Direct Torque Control ◽  
Motor Drives ◽  
Torque Control ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Flux Estimation ◽  
Stator Flux

<p>Stator flux estimation using voltage model is basically the integration of the induced stator back electromotive force (emf) signal. In practical implementation the pure integration is replaced by a low pass filter to avoid the DC drift and saturation problems at the integrator output because of the initial condition error and the inevitable DC components in the back emf signal. However, the low pass filter introduces errors in the estimated stator flux which are significant at frequencies near or lower than the cutoff frequency. Also the DC components in the back emf signal are amplified at the low pass filter output by a factor equals to . Therefore, different integration algorithms have been proposed to improve the stator flux estimation at steady state and transient conditions. In this paper a new algorithm for stator flux estimation is proposed for direct torque control (DTC) of induction motor drives. The proposed algorithm is composed of a second order high pass filter and an integrator which can effectively eliminates the effect of the error initial condition and the DC components. The amplitude and phase errors compensation algorithm is selected such that the steady state frequency response amplitude and phase angle are equivalent to that of the pure integrator and the multiplication and division by stator frequency are avoided. Also the cutoff frequency selection is improved; even small value can filter out the DC components in the back emf signal. The simulation results show the improved performance of the induction motor direct torque control drive with the proposed stator flux estimation algorithm. The simulation results are verified by the experimental results.</p>

scholarly journals Fuzzy-Logic Method and Sliding-Mode Control for Induction Motor

2019 ◽  
Vol 8 (6S2) ◽  
pp. 423-427
Keyword(s):  
Fuzzy Logic ◽  
Steady State ◽  
Induction Motor ◽  
Sliding Mode ◽  
Acoustic Noise ◽  
Direct Torque Control ◽  
Variable Structure ◽  
Torque Control ◽  
Structure Control ◽  
Stator Flux

Direct torque control (DTC) is known to generate fast and robust control for induction motor drives. Even though, in classical DTC, there exists a notable ripple in torque and flux during steady state, which can be reflected towards the speed response and generating undesirable acoustic noise. This paper introduces two approaches based on variable structure control (VSC) and fuzzy logic control (FLC) to mitigate steady state chattering problem while preserving the merits of DTC operation. The inverter is controlled directly on the basis of stator flux and the torque errors, by selecting most appropriate voltage vector from switching logic table. A comparative study is performed for the three control topologies including conventional DTC and simulation results are presented and discussed. It is concluded that SMC and intelligent control based technique provide better characteristics in steady state operation with regards to the conventional DTC

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