A Review of the DTC Controller and Estimation of Stator Resistance in IM Drives

2015 ◽  
Vol 6 (3) ◽  
pp. 554 ◽  
Author(s):  
Naveen Goel ◽  
Ram Narayan Patel ◽  
Saji Chacko
Keyword(s):  
Control Method ◽  
Direct Torque Control ◽  
Torque Ripple ◽  
Industrial Applications ◽  
Torque Control ◽  
Estimation Methods ◽  
Flux Linkage ◽  
Voltage Vector ◽  
Stator Flux ◽  
Stator Resistance

<span>In recent years an advanced control method called direct torque control (DTC) has gained importance due to its capability to produce fast torque control of induction motor. Although in these systems such variables as torque, flux modulus and flux sector are required, resulting DTC structure is particularly simplistic. Conventional DTC does not require any mechanical sensor or current regulator and coordinate transformation is not present, thus reducing the complexity. Fast and good dynamic performances and robustness has made DTC popular and is now used widely in all industrial applications. Despite these advantages it has some disadvantages such as high torque ripple and slow transient response to step changes during start up. Torque ripple in DTC is because of hysteresis controller for stator flux linkage and torque. The ripples can be reduced if the errors of the torque and the flux linkage and the angular region of the flux linkage are subdivided into several smaller subsections. Since the errors are divided into smaller sections different voltage vector is selected for small difference in error, thus a more accurate voltage vector is selected and hence the torque and flux linkage errors are reduced. The stator resistance changes due to change in temperature during the operation of machine. At high speeds, the stator resistance drop is small and can be neglected. At low speeds, this drop becomes dominant. Any change in stator resistance gives wrong estimation of stator flux and consequently of the torque and flux. Therefore, it is necessary to estimate the stator resistance correctly. This paper aims to review some of the control techniques of DTC drives and stator resistance estimation methods.</span>

Direct Torque Control for a Bearingless Induction Motor Based on Model prediction

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ding Wang ◽  
Zebin Yang ◽  
Xiaodong Sun ◽  
Weiming Sun ◽  
Haitao Mei
Keyword(s):  
Phase Angle ◽  
Direct Torque Control ◽  
Torque Ripple ◽  
Torque Control ◽  
Electromagnetic Torque ◽  
Flux Linkage ◽  
Content Type ◽  
Voltage Vector ◽  
Space Voltage Vector ◽  
Stator Flux

Purpose The purpose of this paper is to address the large stator flux linkage ripple and electromagnetic torque ripple caused by the hysteresis comparator in traditional direct torque control for a bearingless induction motor (BIM). Design/methodology/approach Model predictive direct torque control (MPDTC) strategy is adopted. On the basis of the mathematical model of BIM, the stator current and stator flux observational values are obtained, and the electromagnetic torque and stator flux at the next moment are predicted. Then, based on the relationship between the stator flux and the electromagnetic torque, the predicted stator flux can be transformed into an equivalent flux linkage vector, which eliminates the weighting coefficients problem among multiple variables in traditional objective functions. The objective function and torque PI controller will output the optimal stator flux linkage and the increments of the torque phase angle. Through the phase angle increments, the space voltage vector can be obtained by the reference flux linkage controller instead of the stator flux linkage and the torque hysteresis controller. Findings The proposed MPDTC method can effectively improve the stator flux linkage and the torque ripple. It can implement the stable suspension of the rotor and improve the dynamic performance and steady-state accuracy of the BIM system. Originality/value A MPDTC strategy is proposed to reduce the ripple of stator flux and electromagnetic torque. The phase angle increment angle of stator flux linkage and electromagnetic torque is optimized by model prediction, and the optimal space voltage vector is obtained by designing the reference flux controller.

scholarly journals Evaluation of Direct Torque Control with a Constant-Frequency Torque Regulator under Various Discrete Interleaving Carriers

Electronics ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 820 ◽  
Author(s):  
Ibrahim Mohd Alsofyani ◽  
Kyo-Beum Lee
Keyword(s):  
Control Method ◽  
Dynamic Performance ◽  
Direct Torque Control ◽  
Induction Machine ◽  
Torque Ripple ◽  
Torque Control ◽  
Permanent Magnet Motors ◽  
Constant Frequency ◽  
Single Carrier ◽  
Stator Flux

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.

scholarly journals Squirrel cage induction motor predictive direct torque control based on multi-step delay compensation

2021 ◽  
Vol 10 (3) ◽  
pp. 244
Author(s):  
Najimaldi M. Abbas
Keyword(s):  
Direct Torque Control ◽  
Reference Value ◽  
Torque Control ◽  
Delay Compensation ◽  
Flux Linkage ◽  
Squirrel Cage ◽  
Voltage Vector ◽  
Squirrel Cage Induction Motor ◽  
Stator Flux ◽  
Cage Induction Motor

The squirrel cage induction motor direct torque control main problems due to torque and large stator flux pulsation. In this an improved model predictive direct torque control algorithm considering multi-step delay compensation is proposed. At each sampling moment, predict the stator flux linkage and torque at the next moment under each voltage vector. The optimal voltage vector deviation from the stator flux linkage reference value and torque reference value are selected as the minimum objective function. Aiming at the problem of one-shot delay in digital control systems, a multi-step predictive delay compensation measure is studied. Simulation shows that the algorithm can effectively reduce torque and stator flux pulsation, reduce current harmonic distortion, and solve the delay problem in digital systems.

Research on ALA+SPM Rotor Synchronous Motor Direct Torque Control

2010 ◽  
Vol 121-122 ◽  
pp. 866-871
Author(s):  
Xue Zhen Chen
Keyword(s):  
Permanent Magnet ◽  
Control Method ◽  
Direct Torque Control ◽  
Synchronous Motor ◽  
Torque Control ◽  
Flux Linkage ◽  
Permanent Magnet Motor ◽  
Maximum Torque ◽  
Stator Current ◽  
Stator Flux

This paper compares the electromagnet torque characteristics of ALA+PM rotor synchronous motor with the conventional permanent magnet motor, the former holds on linearity relationship with the increase of the stator flux linkage, but the later needs restrict condition. The direct electromagnet torque control is the best control method for ALA+PM rotor synchronous motor, but the stator current can increase if the stator flux linkage is bigger or smaller than magnet flux linkage, the maximum torque current percent ampere control method is used to overcome the disadvantage.

scholarly journals Performance Improvement of Servo Control System Driven by Novel PMSM-DTC Based On Fixed Sector Division Criterion

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2154 ◽  
Author(s):  
Dazhi Wang ◽  
Tianqing Yuan ◽  
Xingyu Wang ◽  
Xinghua Wang ◽  
Yongliang Ni
Keyword(s):  
Control System ◽  
Performance Improvement ◽  
Error Compensation ◽  
Permanent Magnet Synchronous Motor ◽  
Direct Torque Control ◽  
Torque Control ◽  
Servo Control ◽  
Flux Linkage ◽  
Servo Control System ◽  
Stator Flux

In order to improve the performance of the servo control system driven by a permanent magnet synchronous motor (PMSM) under novel direct torque control (NDTC), which, utilizing composite active vectors, fixed sector division criterion, is proposed in this paper. The precondition of the accurate compensations of torque and flux errors is that the sector where the stator flux linkage is located can be determined accurately. Consequently, the adaptive sector division criterion is adopted in NDTC. However, the computation burden is inevitably increased with the using of the adaptive part. On the other hand, the main errors can be compensated through SV-DTC (DTC-utilizing single active vector), while another active vector applied in NDTC can only supply the auxiliary error compensation. The relationships of the two active vectors’ characteristics in NDTC are analyzed in this paper based on the active factor. Furthermore, the fixed sector division criterion is proposed for NDTC (FS-NDTC), which can classify the complexity of the control system. Additionally, the switching table for the selections of the two active vectors is designed. The effectiveness of the proposed FS-NDTC is verified through the experimental results on a 100-W PMSM drive system.

The Implementation of Permanent Magnet Synchronous Motor Direct Torque Control

2013 ◽  
Vol 712-715 ◽  
pp. 2757-2760
Author(s):  
Jun Li Zhang ◽  
Yu Ren Li ◽  
Long Fei Fu ◽  
Fan Gao
Keyword(s):  
Coordinate System ◽  
Permanent Magnet ◽  
Control Method ◽  
Block Diagram ◽  
Permanent Magnet Synchronous Motor ◽  
Direct Torque Control ◽  
Torque Ripple ◽  
Synchronous Motor ◽  
Torque Control ◽  
Two Phase

In order to deeply understand the characteristics of the permanent magnet synchronous motor direct torque control method, its mathematical models were established in the two-phase stationary coordinate system, the two-phase synchronous rotating coordinate system, and x-y stator synchronous rotating coordinate system. The implementation process of direct torque control method in varied stator winding connection was analyzed in detail. In order to improve the speed and torque performance of the permanent magnet synchronous motor, the direct torque control block diagram and the space voltage vector selection table were given. Finally, the summary and outlook of reducing torque ripple in the permanent magnet synchronous motor direct torque control methods.

Study on speed sensorless system of permanent magnet synchronous motor based on improved direct torque control

2021 ◽  
pp. 014233122110629
Author(s):  
Xiaoxin Hou ◽  
Mingqian Wang ◽  
Guodong You ◽  
Jinming Pan ◽  
Xiating Xu ◽  
...  
Keyword(s):  
Control System ◽  
Permanent Magnet ◽  
Permanent Magnet Synchronous Motor ◽  
Direct Torque Control ◽  
Torque Ripple ◽  
Synchronous Motor ◽  
Torque Control ◽  
Switching Frequency ◽  
Speed Sensorless ◽  
Stator Resistance

The traditional direct torque control system of permanent magnet synchronous motor has many problems, such as large torque ripple and variable switching frequency. In order to improve the dynamic and static performance of the control system, a new torque control idea and speed sensorless control scheme are proposed in this paper. First, by deriving the equation of torque change rate, an improved torque controller is designed to replace the torque hysteresis controller of the traditional direct torque control. The improved direct torque control strategy can significantly reduce the torque ripple and keep the switching frequency constant. Then, based on the improved direct torque control and considering the sensitivity of the stator resistance to temperature change, a speed estimator based on the model reference adaptive method is designed. This method realizes the stator resistance on-line identification and further improves the control precision of the system. The performance of the traditional direct torque control and the improved direct torque control are compared by simulation and experiment under different operating conditions. The simulation and experimental results are presented to support the validity and effectiveness of the proposed method.

scholarly journals Minimization torque ripple for SRM based on flux linkage partition in DB-DTFC

2020 ◽  
Vol 306 ◽  
pp. 04007
Author(s):  
Qianni Li ◽  
Aide Xu ◽  
Chaoyi Shang ◽  
Lepeng Huang
Keyword(s):  
Permanent Magnet Synchronous Motor ◽  
Direct Torque Control ◽  
Torque Ripple ◽  
Torque Control ◽  
Flux Linkage ◽  
Switched Reluctance ◽  
Reluctance Motor ◽  
Calculation Module ◽  
Vector Modulation ◽  
Optimal Space

This paper proposes a novel deadbeat torque and flux control (DB-DTFC) to reduce torque ripple for switched reluctance motor (SRM). DB-DTFC combines the advantages of direct torque control (DTC) and space-vector modulation (SVM). DB-DTFC leads current vector control into DTC in order to find the equation between torque and current through deadbeat prediction theory i.e. a beat reaches a given point. In addition, the deadbeat calculation module here is similar to that of permanent magnet synchronous motor. Based on dq0 reference frame of SRM, the most suitable dq0 axis current of next moment corresponding to different torque errors is calculated and predicted. According to the calculated dq0 axis current, the optimal space voltage vectors can be selected to reduce torque ripple. In order to verify the effectiveness and correctness of the proposed scheme, DB-DTFC is verified and compared with the DTC-SVM by simulation.

Sign in / Sign up

Export Citation Format

Share Document