Reduction Of Flux Ripples Research Articles

Three-Vector-Based Model Predictive Torque Control for Dual Three-Phase PMSM With Torque and Flux Ripples Reduction

Three-Vector-Based Model Predictive Torque Control for Dual Three-Phase PMSM With Torque and Flux Ripples Reduction

Optimization and control of photovoltaic water pumping system using kalman filter based MPPT and multilevel inverter fed DTC-IM

This paper aims to research a photovoltaic solar water pumping system (PVWPS) based on a three-phase induction motor (IM) with high performance, low cost, and without chemical energy storage. The proposed control for the PVWPS consists of two principal controllers. The first controller is used to control the system to reach its maximum using a robust MPPT control strategy that is based on the Kalman filter algorithm (KF-MPPT). While the second controller is based on 12-sectors Direct Torque Control (DTC). This technique is proposed to control the IM with the centrifugal pump through a three-level inverter with a neutral point clamped (NPC) structure. Furthermore, to increase the performance of the proposed control without affecting the system efficiency, the torque and flux hysteresis regulators level is increased to five and three levels, respectively. To see the behaviors of the PVWPS with the proposed control, the whole system was designed and simulated in the MATLAB/Simulink environment. This work also includes a comparative analysis to show the performance of the proposed control compared to the conventional controls. This analysis is done first to compare the performance of the KF-MPPT, VSS-P&O-MPPT, and VSS-INC-MPPT using variable radiation, and then to compare the proposed KF-MPPT-PDTC and the conventional KF-MPPT-DTC under a daily climatic profile. The simulated results showed that PVWPS with KF-MPPT and PDTC provide a better performance in terms of reference tracking, response time, torque and flux ripple reduction, current quality, as well as water pumped.

A computationally efficient torque and flux ripple reduction by active vector optimization approach using direct torque control–based model predictive torque control for matrix converter–fed permanent magnet synchronous motor

The Matrix Converter–fed Finite Control Set–Model Predictive Control is an efficient drive control approach that exhibits numerous advantageous features. However, it is computationally expensive as it employs all the available matrix converter voltage vectors for the prediction and estimation. The computational complexity increases further with respect to the inclusion of additional control objectives in the cost function which degrades the potentiality of this technique. This paper proposes two computationally effective switching tables for simplifying the calculation process and optimizing the matrix converter active prediction vectors. Here, three prediction active vectors are selected out of 18 vectors by considering the torque and flux errors of the permanent magnet synchronous motor. In addition, the voltage vector location segments are modified into 12 sectors to boost the torque dynamic control. The performance superiority of the proposed concept is analyzed using the MATLAB/Simulink software and the real-time validation is conducted by implementing in the real-time OPAL-RT lab setup.

Improved DTC-SVM Based on Input-Output Feedback Linearization Technique Applied on DOEWIM Powered by Two Dual Indirect Matrix Converters

This paper focuses on the application of the direct torque control based on space vector modulation (DTC-SVM), combined with the input–output feedback linearization (IOFL) technique on a three-phase dual open-end windings induction motor (DOEWIM) fed by two dual indirect matrix converters. The main aim of integrating the non-linear technique is to overcome the main drawbacks met within the application of the conventional DTC-SVM on dual-stator induction motor (DSIM), such as the torque and flux ripples reduction, the stator harmonics current minimization, and the elimination of the common-mode voltage (CMV). Furthermore, it is proved in this paper that the proposed control on DOEWIN can ensure more flexibility versus speed reverse and variation, load torque changes, and motor parameters variation. The obtained results prove the validity of the proposed control on the studied induction motor topology in ensuring the main aforementioned advantages compared to the conventional DTC-SVM control on DSIM, which presents a promising solution, especially in industrial applications in which high-power motors are required.

Assessment of Control Drive Technologies for Induction Motor: Industrial Application to Electric Vehicle

Nowadays electric vehicle has increasingly gained much popularity indicated by growing global share market targeted at 30% by 2030 after recording 7.2million global stock in 2019. Compared to Internal Combustion Engine (ICE) counterpart, Battery Electric Vehicles (BEV) produce zero tailpipe emission which greatly reducing carbon footprints. Induction motor has been widely used and its control technology has evolved from scalar type volt/hertz to recent predictive control technology. This allows induction motor’s application to expand from being the workhorse of industry to become prime mover in electric vehicle, where high performance is expected. Among vector control scheme, Direct Torque Control (DTC) has gained interest over Field Oriented Control (FOC) with simpler structure, better robustness and dynamics performance yet suffer from high torque and flux ripple. In electric vehicle applications, high ripple at low speed is highly undesirable, potentially causing torsional vibration. High performance control requires speed sensor integration, which often increase complexity in the design. The work aims to review the best control technology for induction motor in electric vehicle application through performance parameter evaluation such as improvement on dynamic response, torque and flux ripple reduction, and component optimization. Several arise issues in motor control and possible methods to circumvent are highlighted in this work. In conclusion, model predictive torque control (MPTC) is the most promising scheme for electric vehicle with excellent dynamic response, good low speed performance, and 50% torque ripple reduction compared to conventional DTC and potential integration with sliding mode observer for sensorless solution.

DISCRETE SWITCHING STRATEGY FOR DIRECT TORQUE CONTROL OF INDUCTION MOTOR USING ADAPTIVE PULSE WIDTH MODULATOR

The Direct Torque Control on Space Vector Modulator of Induction motor is modeled to reduce the torque ripples. The conventional approaches are used various controlling strategies for determining the performance of motor drive system. Here the controlling section mainly utilized with switching activity of the device. Here the proposed model is designed to rectify the problem of overcoming the modulation at high speed Induction motor. In proposed DTC of Induction Motor, designed with discrete switching activity by generating the gated pulse from PWM and it is modeled based on the Space Vector Modulator. The discrete switching activity is performed with referring peak voltage and offset voltage with initial state of zero. By adding these voltages, the vector voltage is generated to occupy the SVM - Induction machine; therefore, this reduces the torque ripples and harmonic signals. Here the adaptive pulse width modulator generates the pulse by controlling the torque and flux ripples using PI controller. The experimental result shows the 4.3% reduction of torque ripples and 0.7% reduction of flux ripples. This makes the discrete clock switching for performing the Induction motor. The closed loop flux controlling strategy is enabled to perform best result of rated speed, torque and stator flux. By analyzing various conventional methods, the proposed model utilized to obtain better result. The overall design is done with the help of MATLAB/2018a tool.

Model predictive combined vector and direct torque control of SM‐PMSM with MTPA and constant stator flux magnitude analysis in the stator flux reference frame

This study presents a combined vector and direct torque control (CVDTC) for surface-mounted permanent magnet synchronous motor (SM-PMSM). The CVDTC method has a fast dynamic torque response without requiring any conventional PWM signal-generators. Besides, it provides low-speed control and standstill operation, torque and flux ripple reduction, minor switching frequency variations, and low computational burden. In this study, CVDTC is mathematically analysed in the stator flux reference frame and then both DTC and CVDTC are simulated and compared for SM-PMSMs. To further reduce torque and flux ripple, model predictive combined vector and direct torque control (MPCVDTC) with the finite control set is analysed and proposed in the stator flux reference frame. Moreover, maximum torque per ampere (MTPA) and constant stator flux magnitude analysis for SM-PMSM are explored in the stator flux reference frame. Simulation and experimental results substantiate the effectiveness and performance of the CVDTC and MPCVDTC methods over a vast speed range.

Predictive Torque and Stator Flux Control for N*3-Phase PMSM Drives With Parameter Robustness Improvement

In this article, a novel predictive torque and stator flux control (PTSF) method is proposed for N -segment three-phase permanent magnet synchronous motor ( N *3-phase PMSM), which can effectively eliminate the influence of parameter mismatch on stator flux and torque. The proposed PTSF method has two loops, stator flux loop and torque loop, both implemented with robust predictive control algorithm. First, the stator flux predictive controller with parameter robustness is designed, and the sensitivity of its parameters is analyzed. In the dq stator flux space, the robust stator flux predictive control with one-step delay compensation is then proposed, which can effectively enhance robustness against parameters mismatch. Moreover, the robust torque predictive control based on unknown torque disturbance observer is developed, which can effectively strengthen the robustness against the load torque disturbance and parameter mismatch. Finally, the validity and feasibility of the proposed PTSF method are verified by simulation and experiment. Excellent simulation and experimental results were achieved with respect to the stator flux tracking error, torque /flux ripple reduction, and stator current distortion over conventional predictive torque control.

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

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.

Design, Implementation and Control of a SiC-Based T5MLC Induction Drive System

This paper presents and evaluate a prototype of an advanced topology of five-level T-type MLC, namely “T5MLC”, implemented within a complete AC induction drive. The evaluation is based on the ability of balancing the converter DC link capacitor voltages, the torque and flux ripples reduction of the induction motor under control, the harmonic analysis and the efficiency of the inverter and the overall drive system. The converter implementation and design considerations using Silicon Carbide (SiC) discrete MOSFETs are discussed. The operation and the analytical model of T5MLC using switching-functions are presented. The model predictive control (MPC), as a preferred AC drive control approach, is selected to adapt the machine torque and flux, and to balance the DC link capacitor voltages. The T5MLC drive system is tested at different scenarios; i.e. suddenly load changing and speed reversal, to ensure the converter capability and excellent performance in AC drive applications. The experimental results show that the MPC could achieve an excellent performance in terms of low harmonic distortions, reduced flux and torque ripples and the ability of balanced DC link capacitors. In addition, the loss analysis showed that the T5MLC is 5.5 % to 24.8 % efficient compared to dual T-type MLC at different loading conditions.

Optimization and control of water pumping PV systems using fuzzy logic controller

The aim of this work is to search for better control and optimization of a photovoltaic (PV) water pumping system (PWPS) using the induction motor. A proposed method based on Fuzzy Logic Control (FLC) is introduced and investigated to improve the conventional Direct Torque Control (DTC). Variable step size Perturb and observe (P&O) is used to extract the maximum possible power from the PV panel. The validation of the control strategy is ensured by reducing the high torque, stator flux ripples and current harmonics in induction machine and increasing pumped water flow. Simulation results of the DTC based on FLC are compared with those of the conventional DTC using MATLAB/SIMULINK. The comparison results show the effectiveness of the FLC controller in terms of torque and flux ripples reduction, and daily pumped water.

Stator current and rotor flux ripples reduction of DTC DFIG drive using FSTSMC algorithm

Over the past years, many kinds of control techniques are proposed for DFIG drives. Among them, the DTC control scheme has gained more importance due to simple control schemes and fast dynamic response. However, it has the disadvantage of high ripples in stator current, rotor flux, torque, and slow response because of hysteresis controllers in torque and rotor flux loop. To improve the performance of direct torque control technique and to minimize the rotor flux and stator current ripples, DTC strategy based fuzzy super-twisting sliding mode controllers (FSTSMC) is proposed in this work. The simulation is carried out using Matlab software and compares the DTC strategy with proportional-integral (PI) controllers and the proposed control scheme is implemented and simulated results are shown.

Design and implementation of DTC based on AFLC and PSO of a PMSM

Direct Torque Control (DTC) of the permanent magnets synchronous motor (PMSM) is receiving increasing attention due to important advantages, such as high performance and low dependence on motor parameters. Recently, intelligent approaches were proposed to improve the DTC performance, in particular the torque and the flux ripples reduction. In this paper, Adaptive Fuzzy Logic Control (AFLC) and Particle Swarm Optimization (PSO) based DTC schemes are developed as alternative approaches to classical DTC. The AFLC technique uses two fuzzy controllers; the first AFLC supervises the tuning of the conventional speed loop PI regulator, while the second AFLC replaces the conventional DTC comparators. The second technique uses the PSO to optimize the speed loop PI regulator. Simulation and experimental results illustrate that the proposed intelligent techniques can effectively reduce flux and torque ripples with better dynamic and steady-state performance.

Direct Torque Control for Permanent-Magnet Synchronous Machines Based on Duty Ratio Modulation

This paper proposes a novel duty ratio modulated direct torque control (DDTC) to concurrently reduce torque ripple and stator flux ripple that are typically associated with conventional direct torque control (DTC). Three different methods of duty ratio determination are presented to achieve various control objectives, namely DDTC-final, DDTC-mean and DDTC-rms. Additionally, adjustable error weight coefficients are introduced to balance the torque ripple reduction and stator flux ripple reduction. Experimental results are presented to validate the effectiveness of proposed DDTC. Furthermore, the comparative evaluation of proposed DDTC, conventional DDTC and DTC is conducted on the basis of several criteria to verify the superiority of proposed DDTC.

A New Direct Torque Control Algorithm for Torque and Flux Ripple Reduction

In this study, a novel direct torque control (DTC) algorithm is developed to decrease torque ripple, electromagnetic noise and harmonics in the three phase squirrel caged induction motors. The space vectors of the conventional DTC method, the position of the stator flux vector and deviation from the reference flux are utilized to construct the new algorithm. Switching time of the vectors in the proposed algorithm is determined from a switching table which is based on the flux error. Switching time pairs in the table are selected using the flux error and the position of the sector. This table eliminates need for complex mathematical operations to determine the switching time of the space vectors in the induction motors and maximizes the performance of the algorithm. The algorithm is simulated and tested by an experimental setup. Simulation and experimental results suggest that the proposed algorithm decreases torque ripple and current harmonic and it has adequate dynamic and steady-state torque performance. Compared to the conventional DTC, the new algorithm has lower EMI noise level

A Novel Duty Cycle Control Strategy to Reduce Both Torque and Flux Ripples for DTC of Permanent Magnet Synchronous Motor Drives With Switching Frequency Reduction

Conventional switching-table-based direct torque control (DTC) presents large torque and flux ripples as well as variable switching frequency. Many methods have been proposed to tackle the aforementioned problems, among which duty cycle control is a kind of very effective approach. It is known that by adjusting the duty ratio of the active vector selected from the switching table, the torque ripple can be reduced. However, most of the prior duty cycle control methods only focus on the torque performance improvement and fail to take the flux ripple reduction into account. Furthermore, the methods obtaining the duty ratio are usually complicated and relies heavily on the accuracy of machine parameters, which negates the merits of simplicity and robustness of conventional DTC. This paper proposes a unified switching table to select three vectors rather than two vectors in prior arts; hence, lower flux ripple and more sinusoidal stator current can be obtained while maintaining the torque performance. A very simple but effective method is proposed to obtain the durations of the three vectors. The influence of one-step delay caused by digital implementation is investigated. By arranging the switching sequence of the three vectors appropriately, the switching frequency can be significantly reduced. The superiority of the novel method is confirmed by a comparative study with its counterpart using two vectors only. Both simulation and experimental results obtained from a 1-kW permanent magnet synchronous motor (PMSM) DTC drive are presented to validate the effectiveness of the novel duty cycle control strategy.

A Simple Method to Reduce Torque Ripple in Direct Torque-Controlled Permanent-Magnet Synchronous Motor by Using Vectors With Variable Amplitude and Angle

In this paper, a modified direct torque control (DTC) for permanent-magnet synchronous machines, which enables important torque- and flux-ripple reduction by using voltage vectors with variable amplitude and angle, is proposed. In the proposed DTC, the amplitudes of torque and flux errors are differentiated and employed to regulate the amplitude and angle of the output voltage vectors online, which are finally synthesized by space-vector modulation (SVM). Two simple formulas are developed to derive the amplitude and angle of the commanding voltage vectors from the errors of torque and flux only. The conventional switching table and hysteresis controllers are eliminated, and a fixed switching frequency is obtained with the help of SVM. Stator flux is estimated from an improved voltage model, which is based on a low-pass filter with compensations of the amplitude and phase. The proposed DTC is comparatively investigated with the existing SVM-DTC from the aspects of theory analysis, computer simulation, and experimental validation. The simulation and experimental results prove that the proposed DTC is very simple and provides excellent steady-state response, quick dynamic performance, and strong robustness against external disturbance and control-parameter variations.

A New Torque and Flux Controller for Direct Torque Control of Induction Machines

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This paper presents the implementation of a high-performance direct torque control (DTC) of induction machines drive. DTC has two major problems, namely, high torque ripple and variable switching frequency. In order to solve these problems, this paper proposed a pair of torque and flux controllers to replace the hysteresis-based controllers. The design of these controllers is fully discussed and a set of numerical values of the parameters for the proposed controllers is given. The simulation of the proposed controllers applied to the DTC drive is presented. The simulation results are then verified by experimental results. The hardware implementation is mainly constructed by using DSP TMS320C31 and Altera field-programmable gate array devices. The results prove that a significant torque and stator flux ripples reduction is achieved. Likewise, the switching frequency is fixed at 10.4 kHz and a more sinusoidal phase current is obtained. </para>