Direct Torque Control Technique Research Articles

Model-free predictive flux vector control for N ∗ 3-Phase PMSM drives considering parameters mismatch

This paper develops a novel model free-predictive flux vector control method (MF-PFVC) for high-performance stator flux and torque monitoring of the multi-module three-phase PMSM (N ∗ 3-Phase PMSM) drive with parameters mismatch. The proposed MF-PFVC method is based on a convenient combination of direct predictive torque control (PTC) and model free predictive control techniques. First, the voltage source inverter (VSI) vector control of N ∗ 3-Phase PMSM is determined by the three-segment stator windings structure. Then, the parameter mismatch sensitivity of the N ∗ 3-Phase PMSM drive system is analyzed based on the conventional PTC. Furthermore, a novel MF-PFVC method with multivariable unknown disturbance integral terminal sliding mode observer (SMO) is proposed for N ∗ 3-Phase PMSM drive, which can effectively enhance robustness against the parameters mismatch. Finally, compared with the conventional PTC, the simulation and experimental results of MF-PFVC method illustrated improved stator flux control performance concerning lower stator flux ripple as well as reduced torque ripple while it can eliminate the influence of parameter mismatch.

Low-Cost DTC Drive Using Four-Switch Inverter for Low Power Ranges

The direct torque control (DTC) strategy was proposed more than 25 years ago. It is one of the most successful and reliable techniques for AC motors. This paper presents the application of DTC using a four-switch inverter, as one of the non-conventional economic topologies suitable for low power ranges. The experimental prototype proves the validity and effectiveness of the investigated configuration. In addition, for comparison purposes, the DTC technique has been implemented using a conventional six-switch inverter. According to the experimental results, the DTC-based four-switch inverter would be competitive with the conventional topology in low power ranges to achieve an economic AC drive with a satisfactory transient and steady-state performance at moderate costs.

Enhanced Induction Motor Control Using Deep Reinforcement Learning and PWM with DTC

This article presents an enhanced approach for controlling an induction motor, combining Deep Reinforcement Learning (DRL), Pulse Width Modulation (PWM), and a Speed Controller. Flux, torque, and ripples in the stator current are problems with the traditional Direct Torque Control (DTC). A 12-sector DTC technique is suggested to overcome these problems and get rid of torque ripple. In order to reduce the ripples in the stator current vectors brought on by white noise, an enhanced Q-learning-based Kalman filter (IQL-KF) is also employed. The rotation speed and flux control are achieved using fuzzy VIKOR. Simulation data with various load conditions, processing, and noise power covariances are utilized to estimate the effectiveness of the suggested technique. Comparison with the typical DTC approach demonstrates that the suggested method outperforms in transient situations, as assessed by the integrated time absolute error performance index, undershoot, and ripple of crucial parameters.

Developed an Improved Fractional Ordered Darwinian Particle Swarm Optimization Using Fuzzy Logic Controller to Improve the Performance Measures on E-Vehicle

This study introduces the improved fractional ordered Darwinian particle swarm optimization (IFODPSO) method combined with fuzzy logic controllers to optimize motor performance. By utilizing direct torque control (DTC) techniques controlled by IFODPSO, the system achieves quick response times and instantaneous torque generation. The research addresses the optimization of motor performance using the IFODPSO approach for combination with fuzzy logic controllers. The specific problem being addressed is the control of torque in motor applications. The scope of the research includes comparing the performance of the IFODPSO-FLC approach with common field-oriented control (FOC) as well as DTC approaches. The significance of the results attained is noteworthy as the IFODPSO-FLC approach demonstrates promising outcomes in terms of torque control compared to traditional FOC and DTC techniques. Additionally, the proposed PI-fuzzy opposition estimation helps improve system efficiency at low speeds by compensating for variations in stator resistance. The combination of fuzzy logic controllers and Darwinian particle swarm optimization of fractional order approaches presents a novel and efficient solution. The results are evaluated using MATLAB-Simulink, and the obtained performance demonstrates the potential for successful motor control applications.

Comparison of Two Fractional-Order High-Order SMC Techniques for DFIG-Based Wind Turbines: Theory and Simulation Results

Two new nonlinear techniques are proposed in this study for improving the performance and efficiency of the doubly-fed induction generator (DFIG)-based wind turbine systems. Direct torque control (DTC) is among the most widely used strategies for controlling DFIGs due to its many advantages, such as robustness, simplicity, and fast response dynamics. However, this control causes big ripples in both torque and flux. Furthermore, it has significant total harmonic distortion (THD). Several solutions are proposed to overcome these problems, including nonlinear techniques and intelligent strategies such as genetic algorithms. In this work, two different controllers are proposed to improve the performance of the DTC technique. Firstly, the second-order continuous sliding mode (SOCSM) based on fractional-order (FO) control, and secondly, the super twisting algorithm (STA) based on the FO technique. The biggest advantages of the proposed strategies are their durability and ease of execution. Based on the proposed controls, the DTC strategy can greatly improve generator performance in different operating conditions. This paper also provides a comparative analysis of DTC-FOSOCSMC, DTC, and DTC-FOSTA in terms of reference tracking, robustness, chattering reduction, and computational complexity, using mathematical theory and simulation carried out in Matlab/Simulink using a 1.5 MW DFIG-based wind turbine. The simulation results demonstrate the effectiveness and high performance of the proposed DTC techniques.

A simple duty cycle control technique to minimize torque ripple in open-end winding induction motor

Modern electric vehicles (EVs) that drive an induction motor (IM) fed by a traction inverter are fast gaining popularity due to their simple configuration and robustness. The direct torque control (DTC) technique is one of the best control methods to drive the IM, especially in open-end winding configurations, as it offers more voltage vectors. However, the existence of hysteresis controllers and improper switching technique causes larger torque ripples that leads to variable switching frequency. The study will be focused on the open-end winding induction motor where the direct current (DC) power is fed from both sides of the stator windings using the dual inverter configuration. To minimize the torque ripples, a simple switching technique using the duty cycle control method is proposed by injecting a high-frequency square wave into the default inverter switching status to form the new pattern of voltage vectors. The effectiveness of the proposed technique is tested through MATLAB/Simulink software and validated experimentally with a lab-scale setup using a dSPACE controller. The findings show that the proposed method reduces torque ripple by over 50% while keeping the DTC's simple structure.

Direct Torque Control of an Induction Motor Using Fractional-Order Sliding Mode Control Technique for Quick Response and Reduced Torque Ripple

The performance of electric drive propulsion systems is often degraded by the high torque and flux ripples of an electric drive. Traditional control methods, such as proportional plus integral (PI) controllers and classical sliding mode controllers (SMCs), have shown good response and reduced torque ripple, but even lower ripple content at low voltage levels is required for its effective use in electric vehicle (EV) applications. In this paper, a new direct torque control (DTC) technique with space vector pulse width modulation (SVPWM) using fractional-order sliding mode control (FOSMC) for a two-level inverter (2LI) at constant switching frequency is proposed. The effectiveness of this proposed controller is compared with a conventional proportional-integral controller and a conventional sliding mode controller (SMC). Simulink models are developed using MATLAB version R2018a to analyze the robustness of the proposed control strategy. Simulation results demonstrate the advantage of the proposed controller in reducing the torque ripples at steady state with less settling time during sudden load change conditions. The proposed control technique also demonstrates better utilization of the stator flux through flux trajectory waveforms.

Open-Phase Fault-Tolerant DTC Technique for Three-Level NPC VSI-Fed Five-Phase Induction Motor Drives

The demand for motor drives based on multiphase machines (MMs) is increasing due to their inherent fault-tolerant capabilities. To achieve satisfactory post-fault operation, a proper fault-tolerant controller is needed. Some direct-torque-control (DTC) techniques have been reported for five-phase induction motor (FPIM) drives under an open-phase fault (OPF). DTC offers simplicity, fast response, and less parameter sensitivity. However, the existing fault-tolerant DTC methods were designed for two-level voltage-source inverters (VSIs). A three-level neutral-point-clamped (NPC) VSI allows greater flexibility in the switching states, lower current and torque ripple, and reduced common-mode voltage (CMV). However, the increased number of switching states requires the design of new DTC methods, able to tolerate OPFs while providing satisfactory performance in various aspects. In this article, two fault-tolerant DTC techniques are developed for three-level NPC VSI-fed FPIM drives under an OPF. The possible switching states are synthesized with suitable virtual vectors (VVs), addressing the dc-link voltage balance, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\text {d}v/\text {d}t}$ </tex-math></inline-formula> , CMV, and dc-link utilization. The two methods are compared under an OPF in these terms, as well as regarding the average switching frequency. Comparative experimental results are provided to assess the viability of the developed DTC schemes at steady-state and dynamic conditions.

Different Control Techniques of Permanent Magnet Synchronous Motor with Fuzzy Logic for Electric Vehicles: Analysis, Modelling, and Comparison

This paper presents a detailed analysis and comparative study of three torque control methodologies with fuzzy logic, namely direct torque control (DTC), fuzzy direct torque control (FDTC), and model predictive direct torque control (MPDTC), for PMSM control applied to an electric vehicle. The three control strategies are designed and developed to control torque in order to achieve vehicle requirements, such as minimum torque and flux ripples, fast dynamic response, and maximum efficiency. To enhance the performance and efficiency of the overall drive, a bidirectional DC/DC buck-boost converter is connected to the Li-ion battery. In addition, a fuzzy logic controller (FLC) is used in the outer loop to control the speed of the PMSM. As a result, the tuning difficulty of the conventional proportional-integral (PI) controller is avoided and the dynamic speed response is improved. Simulation results obtained from the three control techniques establish that the proposed system via the MPDTC technique reduces the torque ripples, flux ripples, reduces the THD of the PMSM current, and achieves a faster transient response. Additionally, the MPTDC technique enabled the electric vehicle to cover the longest distance, with approximately 110.72 km in a charging cycle. The real-time simulation is developed using the RT LAB simulator, and the obtained results confirm the superiority of the MPDTC technique over conventional DTC and FDTC techniques.

A Highly Effective Modified Direct Torque Control for Five Phase Induction Motor without AC Phase Current Sensors

The Direct Torque Control (DTC) technique requires stator currents and DC bus voltage, as well as inverter switch states, in order to estimate stator flux and electromagnetic torque values. Measurement of phase currents in real time with current sensors is a common method of gathering this data. To control a Five-Phase Induction Motor (FPIM), the DTC needs at least four alternating current (AC) sensors and one voltage sensor. When utilized in a global training system, this number has disadvantages due to cost, size, and non-linearity. The purpose of this article is to show how to remove the alternating current sensors from an FPIM's DTC. This is accomplished by reconstructing the phase currents using a simple DC current sensor placed at the voltage inverter's input and modifying the classical DTC control technique by using a good choice of certain allowable switching vectors of a five-phase voltage inverter, the 18° zone offset strategy of the stator flux, and developing a new commutation table for the stator currents construction. The proposed control approach is supported by simulation results.

Performance Analysis of Optimization Based FOC and DTC Methods for Three Phase Induction Motor

Three-phase induction motors are becoming increasingly utilized in industrial field due to their better efficiency and simple manufacture. The speed control of an induction motor is essential in a variety of applications, but it is difficult to control. This research analyses the three-phase induction motor’s performance using field-oriented control (FOC) and direct torque control (DTC) techniques. The major aim of this work is to provide a critical evaluation of developing a simple speed controller for induction motors with improving the performance of Induction Motor (IM). For controlling a motor, different optimization approaches are accessible; in this research, a Fuzzy Logic Controller (FLC) with Fractional Order Darwinian Particle Swarm Optimization (FODPSO) algorithm is presented to control the induction motor. The FOC and DTC are controlled using FODPSO, and their performance is compared to the traditional FOC and DTC technique. Each scheme had its own simulation model, and the results were compared using hardware experimental and MATLAB-Simulink. In terms of time domain specifications and torque improvement, the proposed technique surpasses the existing method.

Various control methods of permanent magnet synchronous motor drives in electric vehicle: a technical review

Day by day use of internal combustion engines (ICE) compared to electric vehicles (EV) is deteriorating because mainly of pollution and their less fuel availability. In the present scenario, an electric vehicle plays a major role in place of an ICE vehicle. So that performance of EV can be improved by proper selection of electric motor. Initially, EV prefers induction motors for traction purposes, but complexity in controlling induction motor, permanent magnet synchronous motor (PMSM) presently used in EV by most of the electric vehicle manufacturers due to its advantages. This paper reviews on various control methods for PMSM used in EV. Various control methods are being used for EV applications. Initially, conventional direct torque control (DTC) technique being used in controlling electric motors but it has a drawback of high torque and flux ripples. Hence, intelligent controllers are predominantly using in controlling PMSM drives.

Investigations of hysteresis based direct torque controlled and field oriented controlled IPM drives for electric vehicle applications

Direct Torque Control (DTC) techniques are widely used in the control of AC machines as an opponent of space vector pulse width modulation (SVPWM) based field-oriented control (FOC). In the literature, hysteresis-based DTC (HB-DTC) is a vast majority of DTC techniques as the technique do not require a position resolver or an encoder. In this study, HB-DTC and FOC techniques are compared in detail by paying particular attention to current distortions, torque ripple and computational burden. In both techniques, the results have been obtained by simulating a 4.1 kW interior mounted permanent magnet synchronous (IPM) motor which has been designed and manufactured for research and development for electric vehicle traction applications. The results validate that although the HBDTC drives, have pros such as having less computational burden on the processor and eliminating the need for a position sensor, they have relatively much current distortions and torque ripple and hence the results are much deteriorated. Since the modern processors can easily deal with higher computational burden and field-oriented control is feasible in real time, it has been validated by extensive simulations that FOC based IPM drives are superior to their HB-DTC counterparts.

Torque/Speed Control of 3PH Synchronous Reluctance Motor Using Direct Torque Control

This paper presents an investigation of the dynamic performance of the synchronous reluctance motor (SynRM) controlled by the Direct Torque Control (DTC) technique to attain either torque or speed control. The system under study comprises synchronous reluctance motor driving a mechanical load. The inner control loop of the DTC algorithm is employed to achieve torque control through the torque hysteresis comparator in which the command torque is set externally as desired. The speed control is accomplished by adding an outer control loop comprising a speed comparator and PID controller. The controller parameters are accurately tuned to provide high transient and improved dynamic performance of the motor. The SynRM model, in the d-q synchronously rotating reference frame, and the overall components of the DTC algorithm are formulated in MATLAB/Simulink. The transient and dynamic response of the SynRM controlled by DTC is investigated when the overall system is subjected to various patterns of torque and speed commands. The results confirmed that the proposed DTC technique attained a stable, fast, and robust response for both torque and speed control loops of the controlled SynRM. Furthermore, the impact of varying the controller sampling time was explored, the outcomes revealed that as the sampling time reduces, the motor dynamic performance is significantly improved.

Modified Direct Torque Control Technique of Induction Motor for Torque Ripple and Common-Mode Voltage Reduction with Neutral-Point Voltage Balancing

Modified Direct Torque Control Technique of Induction Motor for Torque Ripple and Common-Mode Voltage Reduction with Neutral-Point Voltage Balancing

An enhanced control strategy based imaginary swapping instant for induction motor drives

&lt;p&gt;The main aim of this paper is to present a novel control approach of an induction machine (IM) using an improved space vector modulation based direct torque control (SVM-DTC) on the basis of imaginary swapping instant technique. The improved control strategy is presented to surmount the drawbacks of the classical direct torque control (DTC) and to enhance the dynamic performance of the induction motor. This method requires neither angle identification nor sector determination; the imaginary swapping instant vector is used to fix the effective period in which the power is transferred to the IM. Both the classical DTC method and the suggested adaptive DTC techniques have been carried out in MATLAB/SimulinkTM. Simulation results shows the effectiveness of the enhanced control strategy and demonstrate that torque and flux ripples are massively diminished compared to the conventional DTC (CDTC) which gives a better performance. Finally, the system will also be tested for its robustness against variations in the IM parameters.&lt;/p&gt;

Comparative Analysis of Torque Ripple for Direct Torque Control based Induction Motor Drive with different strategies

ABSTRACT Direct Torque Control (DTC) method is one of the most outstanding and proficient control techniques of the induction motor. The foremost drawback of DTC induction motor drive is high torque pulsation, variable frequency of inverter switching. The main reason of torque pulsation is torque and flux hysteresis band utilised in DTC. DTC method is utilising hysteresis comparators which produce high torque pulsation and unpredictable switching frequency. In this paper, torque ripple analysis of fuzzy logic controller (FLC) based Direct Torque Control (DTC) of three-phase induction motor drive has been discussed. The space vector pulse width modulation (SVPWM) based DTC technique, which operates with the regular switching frequency, helps to solve the fundamental issues of torque pulsation. In addition to this, literature proposes different solutions like a prediction scheme, fuzzy logic controller technique, global minimum torque ripple strategy, constant frequency torque controller (CFTC) Technique, optimal switching instant scheme, duty cycle control scheme, SVPWM DTC for torque ripple reduction. The fuzzy logic controller capabilities for DTC technique are applied with the induction motor (IM) drive for high-performance applications. The simulation results of Conventional DTC, SVPWM DTC, Carrier SVPWM DTC and FLC-DTC method for the induction motor are illustrated. Fuzzy-based DTC technique compared with CSVPWM DTC method and conventional DTC method are presented. The torque ripple of 7.4% for 5 HP induction motor is achieved by FLC-based DTC method. Hardware results for DTC induction motor drive are also demonstrated and discussed. This paper presents improvement in torque ripple reduction with the help of carrier space vector pulse width modulation (CSVPWM) and FLC-based DTC.

24 Sectors DTC Control with Fuzzy Hysteresis Comparators for DFIM Fed by the Three-level NPC Inverter

This article presents 24 sectors direct torque control (DTC) with fuzzy hysteresis comparators for the doubly-fed induction motor (DFIM) using a three-level neutral point clamped (NPC) inverter. The designed DTC technique of the DFIM combines the advantages of the DTC strategy and fuzzy logic controller. The reaching conditions, stability, and robustness of the DFIM with the designed DTC technique are guaranteed. The designed DTC technique is insensitive to uncertainties, including parameter variations and external disturbances in the whole control process. Finally, the designed DTC technique with fuzzy hysteresis comparators is used to regulate the electromagnetic torque and the flux of the DFIM fed by the three-level NPC inverter and confirms the validity of the designed DTC technique. Results of simulations containing tests of robustness and tracking tests are presented.

Predictive direct torque control of a rotor-side matrix converter driven grid connected DFIG with torque and flux ripples minimisation criterion

The doubly fed induction generator (DFIG) is the most commonly used machine for variable speed wind power generation, and the single stage matrix converter (MC) can potentially replace the conventional back-to-back voltage source converters (VSCs) for rotor to grid inter connection. In this research work, the performance of grid connected DFIG with rotor side MC is analysed with predictive direct torque control (P-DTC) technique incorporating a criterion for minimising the torque and rotor flux ripples at a fixed switching frequency. Space vector modulation (SVM) is utilised for MC side control. The system exhibits better transient and steady-state behaviour over conventional configurations, for both sub and super-synchronous operating modes, as evaluated by simulation based on a 2 MW DFIG model in MATLAB-Simulink environment.

Broken Rotor Bar and Rotor Eccentricity Fault Detection in Induction Motors Using a Combination of Discrete Wavelet Transform and TeagerKaiser Energy Operator

In this paper, a hybrid approach is proposed to detect the broken rotor bar and rotor mixed eccentricity faults of three-phase squirrel cage induction motors based on one phase of the stator current signal. The hybrid method is based on a combination of discrete wavelet transform (DWT), Teager–Kaiser energy operator (TKEO) and power spectral density (PSD). At the first stage, DWT is applied on the stator current signal; then TKEO is applied on some of the DWT detail coefficients and finally PSD is used to extract the required feature to detect the aforementioned faults. The proposed method is tested on an experimental test-rig having a 1.5 kW induction motor under various load conditions and three different power supplies: 1) directly supplied by power grid; 2) supplied by a drive system based on scalar control technique; and 3) supplied by a drive system based on direct torque control (DTC) technique. The results show the efficacy of the proposed method in accurate detection of the broken rotor bar and rotor mixed eccentricity faults.