scholarly journals Low-Speed Performance Improvement of Direct Torque Control for Induction Motor Drives Fed by Three-Level NPC Inverter

Electronics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 77 ◽  
Author(s):  
Samer Hakami ◽  
Ibrahim Mohd Alsofyani ◽  
Kyo-Beum Lee
Keyword(s):  
Induction Motor ◽  
Direct Torque Control ◽  
Basic Structure ◽  
Motor Drives ◽  
Torque Control ◽  
Low Speed ◽  
Speed Performance ◽  
Sinusoidal Current ◽  
Stator Flux ◽  
Stator Resistance

Classical direct torque control (DTC) is considered one of the simplest and fastest control algorithms in motor drives. However, it produces high torque and flux ripples due to the implementation of the three-level hysteresis torque regulator (HTR). Although, increasing the level of HTR and utilizing multilevel inverters has a great contribution in torque and flux ripples reduction, stator flux magnitude of induction motor (IM) droops at every switching sector transition, particularly at low-speed operation. This problem occurs due to the utilization of a zero voltage vector, where the domination of stator resistance is very high. A simple flux regulation strategy (SFRS) is applied for low-speed operation for DTC of IM. The proposed DTC-SFRS modifies the output status of the five-level HTR depending on the flux error, torque error, and stator flux position. This method regulates the stator flux for both forward and reverse rotational directions of IM with retaining the basic structure of classical DTC. By using the proposed algorithm, the stator flux is regulated, hence pure sinusoidal current waveform is achieved, which results in lower total harmonics distortion (THD). The effectiveness of the proposed DTC-SFRS is verified through simulation and experimental results.

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>

Flux Compensated Direct Torque Control of Induction Motor Drives for Low Speed Operation

2004 ◽  
Vol 19 (6) ◽  
pp. 1608-1613 ◽  
Author(s):  
K.-K. Shyu ◽  
L.-J. Shang ◽  
H.-Z. Chen ◽  
K.-W. Jwo
Keyword(s):  
Induction Motor ◽  
Direct Torque Control ◽  
Motor Drives ◽  
Torque Control ◽  
Induction Motor Drives ◽  
Low Speed

Modified direct torque control method for induction motor drives based on amplitude and angle control of stator flux

2008 ◽  
Vol 78 (10) ◽  
pp. 1712-1718 ◽  
Author(s):  
Yuttana Kumsuwan ◽  
Suttichai Premrudeepreechacharn ◽  
Hamid A. Toliyat
Keyword(s):  
Induction Motor ◽  
Control Method ◽  
Direct Torque Control ◽  
Motor Drives ◽  
Torque Control ◽  
Induction Motor Drives ◽  
Stator Flux

scholarly journals Sensorless Direct Torque Control of the Six-Phase Induction Motor by Fast Reduced Order Extended Kalman Filter

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Asghar Taheri ◽  
Hai-Peng Ren ◽  
Chun-Huan Song
Keyword(s):  
Kalman Filter ◽  
Induction Motor ◽  
Extended Kalman Filter ◽  
Direct Torque Control ◽  
Induction Machine ◽  
Torque Control ◽  
Motor Speed ◽  
Low Speed ◽  
Simplified Algorithm ◽  
Stator Resistance

In this paper, a simple extended Kalman Filter (EKF) controller for direct torque control (DTC) of a six-phase induction machine in all speed ranges is proposed. The aim of this paper is to decrease the execution time of EKF modeling of a six-phase induction motor. The proposed method is fast and can operate online. If the machine parameters are changed during the operation, the EKF algorithm is activated to find parameters used for controlling the motor. In low speed, not only the motor speed measurement but also the DTC of machine is difficult. The EKF model can estimate speed, flux, load torque, and stator resistance in low speed; thus, optimization can be performed in all loads and speed range. The proposed method increases the accuracy of DTC of the six-phase induction machine and decreases the computation cost of the system using the simplified algorithm. The simulation and experimental results verify the effectiveness and the robustness of the proposed method against parameter variations.

Research on Induction Motor DTC System Based on Fuzzy PI Controller

2010 ◽  
Vol 29-32 ◽  
pp. 2200-2204
Author(s):  
Xue Zhi Hu ◽  
Guang Qun Nan
Keyword(s):  
Induction Motor ◽  
Direct Torque Control ◽  
Experimental System ◽  
Torque Ripple ◽  
Torque Control ◽  
Switching Frequency ◽  
System Effect ◽  
Low Speed ◽  
Static Performance ◽  
Stator Flux

Traditional induction motor direct torque control system with the hysteresis loop controller, based on torque error, set the amplitude error to select the inverter switching state, is a Band-Band Control , torque error and stator flux error of level can not be distinguished, switching frequency is not constant, over-sector current and the distortion flux linkage can product low speed torque ripple, affecting the control of the system effect. The paper proposed fuzzy PI control of induction motor direct torque control scheme, a system of principles was introduced, controller parameters was designed by fuzzy theoretical. Finally a full-digital experimental system was built with the TMS320F2812 as the master chip and PM30CSJ060 as an inverter main circuit. Results show that the dynamic and static performance and running smoothly with low-speed is verified.

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