scholarly journals A Torque Impulse Balance Control for Multi-Tooth Fault Tolerant Switched-Flux Machines under Open-Circuit Fault

Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1919 ◽  
Author(s):  
Yu Wang ◽  
Wenjuan Hao
Keyword(s):  
Fault Tolerant ◽  
Balance Control ◽  
Dynamic Performance ◽  
Open Circuit ◽  
Torque Control ◽  
Dynamic State ◽  
Electromagnetic Torque ◽  
Rotor Speed ◽  
Voltage Vector ◽  
Impulse Balance

The multi-tooth fault tolerant switched-flux machines (MTFTSFM) providing both excellent fault tolerant capability and relatively high torque density are good choices for high reliability applications. A rapid control of the electromagnetic torque under open-circuit fault can always be achieved by the direct torque control with voltage vector reconstruction (RDTC); however, with respect to the rotor speed, its dynamic performance is still impacted by the proportion-integration (PI) parameters. Therefore, a torque impulse balance control (TIBC) is investigated in this paper for the MTFTSFM under open-circuit fault to obtain excellent dynamic performance of the rotor speed. During the dynamic state, the electromagnetic torque and the speed can converge at the same time after only one adjustment of the speed by using the optimized voltage vector sequence based on torque impulse balance, thus, achieving the best possible dynamic process for the speed. The TIBC method is carried out on an MTFTSPM machine system, and the correctness and effectiveness are verified.

scholarly journals Fault-Tolerant Control Strategy with Asymmetric Phase Currents for Single to Four-Phase Open-Circuit Faults of Six-Phase PMSM

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3163
Author(s):  
Chen Huang ◽  
Lidan Zhou ◽  
Zujia Cao ◽  
Gang Yao
Keyword(s):  
Working Conditions ◽  
Control Strategy ◽  
Fault Tolerant ◽  
Fault Tolerant Control ◽  
Open Circuit ◽  
Time Varying ◽  
Electromagnetic Torque ◽  
Control Loops ◽  
Phase Current ◽  
Multi Phase

Multi-phase motors and generators are regarded with great fault tolerance capability, especially on open-circuit faults. Various mathematics analytical methods are applied for their fault control. In this paper, a fault-tolerant control strategy with asymmetric phase current for the open-circuit faults with arbitrary phases in the six-phase PMSM (six-phase permanent magnetic synchronous motor, 6P-PMSM) system, is proposed for better electrical and dynamical performance of the machine. An innovative mathematical model for PMSM under one to four-phase-open circuit faults are established considering the asymmetry of the machine. Combining with time-varying relations in machines’ working conditions, targeted decoupling transformation matrixes of every kind of open-circuit faults are settled by voltage equations under different faults. Modified control strategy with a connection between the neutral point and the inverter’s DC side is presented, which aims at increasing the system redundancy and reducing the amplitude of phase currents. Besides, improved control loops with two layers are put forward as well, with which the PMSM system acquires fewer harmonics in phase current and smoother electromagnetic torque. Simulation and experimental results of open-circuit faults are provided for verification of the theoretical analysis.

scholarly journals Switching Sequence Model Predictive Direct Torque Control of IPMSMs for EVs in Switch Open-Circuit Fault-Tolerant Mode

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5593
Author(s):  
Ting Yang ◽  
Takahiro Kawaguchi ◽  
Seiji Hashimoto ◽  
Wei Jiang
Keyword(s):  
Fault Tolerant ◽  
Direct Torque Control ◽  
Open Circuit ◽  
Torque Control ◽  
Flux Linkage ◽  
Switching Sequence ◽  
Space Vectors ◽  
Stator Flux ◽  
Maximum Torque Per Ampere ◽  
Capacitor Voltage Balance

A switching sequence model predictive direct torque control (MPDTC) of IPMSMs for EVs in switch open-circuit fault-tolerant mode is studied in this paper. Instead of selecting one space vector from the possible four space vectors, the proposed MPDTC method selects an optimized switching sequence from two well-designed switching sequences, including three space vectors, according to a new designed cost function of which the control objectives have been transferred to the dq-axes components of the stator flux-linkage under the maximum-torque-per-ampere control. The calculation method of the durations of the adopted space vectors in the optimized switching sequence is studied to realize the stator flux-linkage reference tracking. In addition, the capacitor voltage balance method, by injecting a dc offset to the current of fault phase, is given. Compared with the conventional MPDTC method, the complicated weighting factors designing process is avoided and the electromagnetic torque ripples can be greatly suppressed. The experimental results prove the effectiveness and advantages of the proposed scheme.

scholarly journals Comparative Study of Hysteresis Controller, Resonant Controller and Direct Torque Control of Five-Phase IM under Open-Phase Fault Operation

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1317
Author(s):  
Mahmoud A. Mossa ◽  
Hamdi Echeikh ◽  
Ahmed A. Zaki Diab ◽  
Hassan Haes Alhelou ◽  
Pierluigi Siano
Keyword(s):  
Fault Tolerant ◽  
Direct Torque Control ◽  
Detailed Comparison ◽  
Open Circuit ◽  
Performance Comparison ◽  
Torque Control ◽  
Control Techniques ◽  
Open Phase ◽  
Hysteresis Controller ◽  
Resonant Controller

The need for regulating the operation of unhealthy motor drives has motivated the researchers to modify the control techniques in order to be valid for the new drive state. The use of a fault-tolerant facility is an attractive feature of multiphase machines; therefore, the applicability of different controllers has been established for the operation under open-phase fault conditions. The considered control algorithms were utilized to analyze the operation of the unhealthy system and evaluating the capability of the control to regulate the speed and torque under the fault condition. However, the majority of these studies considered only one control algorithm to be tested with the faulty system without comparing its performance with other techniques. The performance comparison is a vital way to visualize the features and characteristics of each algorithm. For this purpose, this paper deals with the performance comparison of the hysteresis controller, RFOC based on resonant controller and direct torque control (DTC) control under open-circuit fault conditions. A detailed comparison between the three control techniques is presented to outline the main differences between the three control procedures and identify the most appropriate technique in between.

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.

Direct-Torque-Control Fault-Tolerant Strategies for Three Induction Motor Drive Systems Operating Under Single-Phase Open-Circuit Fault

2020 ◽  
Author(s):  
Pedro H. M. Martins ◽  
Victor F. M. B. Melo ◽  
Gilielson F. da Paz ◽  
Isaac S. de Freitas
Keyword(s):  
Induction Motor ◽  
Single Phase ◽  
Fault Tolerant ◽  
Direct Torque Control ◽  
Open Circuit ◽  
Torque Control ◽  
Necessary Condition ◽  
Motor Drive ◽  
Induction Motor Drive ◽  
Drive Systems

This paper discusses Direct-torque-control(DTC)-based fault-tolerance strategiesapplied to three fault-tolerant induction motor drive systems when they operate under single-phase open-circuit fault. Despite the fact that these drive systems have already been discussed in the literature, the reported papers always make use of Field-oriented-control(FOC)-based fault compensation strategies. In this way, performed simulations show that DTC-based strategies are feasible and are able to provide circular flux trajectory, which is the necessary condition for the motor operate properly.

NEURO-GENETIC OBSERVER SPEED FOR DIRECT TORQUE NEURO-FUZZY CONTROL OF INDUCTION MOTOR DRIVE

2012 ◽  
Vol 21 (07) ◽  
pp. 1250060 ◽  
Author(s):  
MOULAY RACHID DOUIRI ◽  
MOHAMED CHERKAOUI ◽  
AHMED ESSADKI
Keyword(s):  
Induction Motor ◽  
Fuzzy Controller ◽  
Dynamic Performance ◽  
Direct Torque Control ◽  
Estimation Method ◽  
Neural Model ◽  
Torque Control ◽  
Actual State ◽  
Rotor Speed ◽  
State Variable

In this work, we applied artificial intelligence techniques to improve the dynamic performance of sensorless direct torque control (DTC). First, we replace the conventional comparator and selection table applied to the DTC induction motor with a neural-fuzzy controller to learn the advantages of both methods; learning capacity of the first and readability and flexibility of the second. This evaluation is obtained using the electromagnetic torque error, the error module and angle of the stator flux vector. Then we propose a new estimation method rotor speed using an adaptive neural observer. The error between the desired state variable and the actual state variable of a neural model is back propagated to adjust the weights of neural model, so that the actual state variable tracks the desired value. Finally, the proportional and integral controller gains are optimized by a genetic algorithm to ensure the optimum performance of rotor speed. The simulation results show the effectiveness of control methods available.

scholarly journals Simulation Study of Two Torque Optimization Methods for Direct Torque-Controlled Induction Motors

2019 ◽  
Vol 9 (24) ◽  
pp. 5547
Author(s):  
Hani Albalawi ◽  
Sherif A. Zaid ◽  
Yonis M. Buswig
Keyword(s):  
Induction Motors ◽  
Dynamic Performance ◽  
Direct Torque Control ◽  
Optimization Methods ◽  
Torque Control ◽  
The Other ◽  
Voltage Vector ◽  
Torque Response ◽  
Parameter Variations ◽  
Dynamic Performances

The simplicity and excellent dynamic performance of Direct Torque Control (DTC) make Induction Motor (IM) drives attractive for many applications that require precise torque control. The traditional version of DTC uses hysteresis controllers. Unfortunately, the nature of these controllers prevents the optimization of the inverter voltage vectors inside the flux hysteresis band. The inverter voltage vector optimization can produce fast torque response of the IM drive. This research proposes two torque optimization methods for IM systems utilizing DTC. Analysis and Matlab simulations for the proposed optimization methods prove that the torque and, consequently, the speed responses, are greatly improved. The performances of the drive system controlled by the proposed optimization methods and the traditional DTC are compared. Conversely, the effects of the parameters on the proposed optimization methods are introduced. The proposed methods greatly improve the torque and speed dynamic performances against the traditional DTC technique. However, one of the proposed optimization methods is more sensitive to IM parameter variations than the other.

scholarly journals Three Vectors Model Predictive Torque Control Without Weighting Factor Based on Electromagnetic Torque Feedback Compensation

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1393 ◽  
Author(s):  
Haixia Li ◽  
Jican Lin ◽  
Ziguang Lu
Keyword(s):  
Pi Controller ◽  
Torque Control ◽  
Model Parameters ◽  
Control Input ◽  
Electromagnetic Torque ◽  
Load Torque ◽  
Outer Loop ◽  
Feed Forward ◽  
Voltage Vector ◽  
Feedback Compensation

Finite control set-model predictive torque control (FCS-MPTC) depends on the system parameters and the weight coefficients setting. At the same time, since the actual load disturbance is unavoidable, the model parameters are not matched, and there is a torque tracking error. In traditional FCS-MPTC, the outer loop—that is, the speed loop—adopts a classic Proportional Integral (PI) controller, abbreviated as PI-MPTC. The pole placement of the PI controller is usually designed by a plunge-and-test, and it is difficult to achieve optimal dynamic performance and optimal suppression of concentrated disturbances at the same time. Aiming at squirrel cage induction motors, this paper first proposes an outer-loop F-ETFC-MPTC control strategy based on a feed-forward factor for electromagnetic torque feedback compensation (F-ETFC). The electromagnetic torque was imported to the input of the current regulator, which is used as the control input signal of feedback compensation of the speed loop; therefore, the capacity of an anti-load-torque-disturbance of the speed loop was improved. The given speed is quantified by a feed-forward factor into the input of the current regulator, which is used as the feed-forward adjustment control input of the speed controller to improve the dynamic response of the speed loop. The range of the feed-forward factor and feed-back compensation coefficient can be obtained according to the structural analysis of the system, which simplifies the process of parameter design adjustment. At the same time, the multi-objective optimization based on the sorting method replaces the single cost function in traditional control, so that the selection of the voltage vector works without the weight coefficient and can solve complicated calculation problems in traditional control. Finally, according to the relationship between the voltage vector and the switch state, the virtual six groups of three vector voltages can be adjusted in both the direction and amplitude, thereby effectively improving the control performance and reducing the flow rate and torque ripple. The experiment is based on the dSPACE platform, and experimental results verify the feasibility of the proposed F-ETFC-MPTC. Compared with traditional PI-MPTC, the feed-forward factor can effectively improve the stability time of the system by more than 10 percent, electromagnetic torque feedback compensation can improve the anti-load torque disturbance ability of the system by more than 60 percent, and the three-vector voltage method can effectively reduce the disturbance.

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