Direct torque control of induction machines with constant switching frequency and improved stator flux estimation

2002 ◽  
Author(s):  
N.R.N. Idris ◽  
A.H.M. Yatim ◽  
N.A. Azli
Keyword(s):  
Direct Torque Control ◽  
Induction Machines ◽  
Torque Control ◽  
Switching Frequency ◽  
Flux Estimation ◽  
Stator Flux

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>

Constant Frequency Torque Controller for DTC with Multilevel Inverter of Induction Machines

2016 ◽  
Vol 7 (1) ◽  
pp. 28
Author(s):  
Norjulia Mohamad Nordin ◽  
Naziha Ahmad Azli ◽  
Nik Rumzi Nik Idris ◽  
Nur Huda Ramlan ◽  
Tole Sutikno
Keyword(s):  
Dynamic Performance ◽  
Direct Torque Control ◽  
Induction Machines ◽  
Torque Control ◽  
Multilevel Inverter ◽  
Switching Frequency ◽  
Constant Frequency ◽  
Hysteresis Controller ◽  
High Torque ◽  
Simulation Results

Direct Torque Control using multilevel inverter (DTC-MLI) with hysteresis controller suffers from high torque and flux ripple and variable switching frequency. In this paper, a constant frequency torque controller is proposed to enhance the DTC-MLI performance. The operational concepts of the constant switching frequency torque controller of a DTC-MLI system followed by the simulation results and analysis are presented. The proposed system significantly improves the DTC drive in terms of dynamic performance, smaller torque and flux ripple, and retain a constant switching frequency.

A Novel Optimal PI Parameter Tuning Strategy to Improve Constant Switching Performance of Direct Torque Control

2016 ◽  
Vol 7 (2) ◽  
pp. 422
Author(s):  
Sundram Ramahlingam ◽  
Auzani Jidin ◽  
Tole Sutikno
Keyword(s):  
Control Structure ◽  
Direct Torque Control ◽  
Parameter Tuning ◽  
Torque Ripple ◽  
Torque Control ◽  
Switching Frequency ◽  
Switching Performance ◽  
Output Torque ◽  
Stator Flux ◽  
Tuning Strategy

<p>This paper presents a novel method of optimal Propotional-Intergral (PI) controller’s parameter tuning strategy in-order to improve the Constant Switching Performance of 3-phase DTC shceme. The Direct Torque Control (DTC) sheme is acknowledged to provide fast decoupled control over the torque output and stator flux via a simple control structure. However, DTC sheme has two major downsides, which are the inconsistent inverter switching frequency and high torque output ripple. The main reason that contributes to these tribulations is the usage of hysteresis comparators in order to control the output torque. The realization of PI based controller method as replacement of hyterisis controller in DTC system able to provide significant solutions to over come the fall back while retaining the simple control structure of conventional DTC. The combination usage of higher sampling controller DS1004 and also 3-level CHMI in this system can further minimize the output torque ripple by providing higher resolution with lower digital error and greater number of vectors. This paper presents detail explanation and calculation of optimal PI parameter tuning strategy consecutively to enhance the performance of 3-level DTC system. In order to verify the feasibility of the proposed method experimentation, the proposed method is compared with convention DTC system via simulation and experiment results.</p>

A Constant Switching Frequency DTC for PMSM Using Low Switching Losses SVM–An Experimental Result

2017 ◽  
Vol 8 (2) ◽  
pp. 558
Author(s):  
K. Chikh ◽  
A. Saad ◽  
M. Khafallah ◽  
D. Yousfi ◽  
F.Z. Tahiri ◽  
...  
Keyword(s):  
Permanent Magnet Synchronous Motor ◽  
Direct Torque Control ◽  
Torque Control ◽  
Experimental Result ◽  
Switching Frequency ◽  
Pwm Inverter ◽  
Switching Losses ◽  
Stator Flux ◽  
Vector Modulation ◽  
Torque Ripples

A Constant Switching Frequency Direct Torque Control (CSF-DTC) with low switching losses Space Vector modulation (SVM) for Permanent Magnet Synchronous Motor (PMSM) drive is proposed in this work. The CSF-DTC combines Field Oriented Control (FOC) and basic DTC advantages. Indeed, the proposed control strategy improves the basic DTC performances, which features low flux and torque ripples as well as a fixed switching frequency. The improved DTC ensures also a fast and robust flux and torque responses by using Integral and Proportional (IP) controllers which guaranteed a good disturbance rejection.On the other hand, a symmetrical SVM technique with low switching losses in the PWM inverter is used in order to generate the desired stator voltage vector needed to control the stator flux and the motor torque. Simulation and experimental results are presentedin this paper.These results demonstrate well the performance of the basic and proposed DTC and they show the effectiveness of the constant switching frequency direct torque control.

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