Torque Ripple Research Articles

Comparative analysis of brushless DC and switched reluctance motors for optimizing off-grid water pumping

Off-grid water pumping systems (OGWPS) have become an increasingly popular area of research in the search for sustainable energy solutions. This paper presents a finite element method (FEM)-based design and analysis of Brushless-DC (BLDC) and Switched Reluctance Motors (SRM) designed for low-power water pumping applications. Utilizing adaptive finite element analysis (FEA), both motors were designed with identical ratings and design parameters to ensure a fair comparison. The design geometries adhere to the NEMA 42 standard. An (n + 1) switch converter topology was implemented to energize SRM phases, while a Cuk converter coupled with a three-phase voltage source inverter (VSI) was used to power the BLDC motor. The study provides a comprehensive comparative analysis of the torque profiles of both motor types under identical operating conditions. The BLDC motor achieved a maximum torque of 11.5 Nm and an efficiency of 91.9%, while the SRM demonstrated a maximum torque of 3.8 Nm and an efficiency of 94.6%. The torque ripple of the BLDC motor was significantly lower (0.73 pu) compared to the SRM (1.19 pu), indicating smoother operation. Simulation results obtained using advanced computational electromagnetic tools highlight the performance efficiencies and potential advantages of each motor type for off-grid water pumping systems. This research investigates the viability of both BLDC and SRM technologies in enhancing the efficiency and reliability of OGWPS, with the BLDC motor showing superior performance in terms of torque and operational smoothness. The simulation results of converter topologies used for respective motors have been further validated using experimentation on respective prototype motors.

Six Sigma-Based Mathematical Optimization Framework for Flux-Switching Machines: A Roadmap for Quality, Performance, and Manufacturing Tolerances

Flux-switching wound field machines (FSWFMs) offer high torque density and independence from rare-earth materials, making them promising candidates for sustainable electric vehicles and industrial applications. However, their adoption is limited by challenges such as high torque ripple, efficiency variations, and sensitivity to manufacturing tolerances. This study presents a Design for Six Sigma (DFSS) optimization framework that integrates sensitivity analysis, response surface modeling (RSM), and multi-objective genetic algorithms to address these challenges. The optimized solution reduces torque ripple by 7.69%, improves torque output, and enhances energy efficiency. By incorporating Six Sigma principles, the framework ensures robust performance under manufacturing variations, bridging the gap between theoretical optimization and practical implementation. This scalable and efficient methodology establishes FSWFMs as viable solutions for industrial applications, revolutionizing electric machine design.

Direct torque tolerant control of five-phase permanent magnet synchronous motor based on super-twisting sliding mode tuned by ISSA

ABSTRACT This paper proposes a fault-tolerant direct torque control strategy based on an improved sparrow search algorithm (ISSA) and super-twisting sliding mode control to address torque ripple and speed response issues in direct torque control (DTC) of five-phase permanent magnet synchronous motor (PMSM). By minimising torque ripple and optimising speed response under load conditions, the traditional dual-hysteresis DTC method is improved, reducing steady-state torque ripple and overshoot in transient speed response. To handle complete rotor position sensor failures, a fault-tolerant control scheme is proposed. A super-twisting sliding mode controller is designed for the flux and torque loops of the DTC, and the improved sparrow search algorithm optimises three controller parameters for the inner and outer loops. The impact of controller complexity on the computational burden is discussed. This ensures that both speed and torque can quickly recover to normal operation after significant disturbances, effectively eliminating chattering. Simulation results demonstrate that the proposed method significantly reduces steady-state torque ripple, achieves rapid speed response, and provides fault tolerance in the event of rotor position sensor failure.

Control of Torque Ripple and Rotor Position for SRM (8/6‐4 Phases) Using an Optimization‐Based Model Predictive Torque Control

ABSTRACTMost electric cars and wind turbines employ switched reluctance motors (SRM), but it has some disadvantages, namely high torque ripple because of its power supply mode and multiphase communication. Model predictive torque control (MPTC) with sailfish optimization (SFO) method is proposed to reduce torque ripple of SRM using torque sharing function (TSF). To develop an efficient torque ripple algorithm, the flux‐linkage characteristic curves are first acquired at protected rotor trial and create an accurate SRM model. It predicts future operation for drive system in SRM architecture. Second, the SFO algorithm is employed to enhance TSF parameters also to minimize the torque value of SRM. Then, the TSF‐based MPTC method is developed to avoid problem like conversion of frequency produced by controller. Finally, atom search optimization (ASO) is used to adjust sensor for correct rotor position of the SRM. To verify the performance of the proposed method, MPTC‐SFO is compared with direct instantaneous torque control (DITC) method. Proposed MPTC‐SFO method attained more efficient result of 12.79% reduced torque ripple than DITC.

Design and analysis of electromagnetic and mechanical structure of ultra-high-speed slotted solid rotor induction motor

In this paper, a high speed slotted solid-rotor induction motor (SSRIM) with rated power of 15 kW and rated speed of 120krpm is studied, and its electromagnetic performance and rotor mechanical structure are optimized. First, according to the empirical formula of motor design, the volume size of the motor is determined. Then, by constructing a two-dimensional finite element model, the slot matching scheme and coil pitch are optimized, and the influence of different slot matching scheme and coil pitch on the output torque and harmonics of the motor is compared. Then, the influence of rotor slot size on electromagnetic and mechanical properties of the motor is described in detail. Finally, a finite element model is constructed to verify the mechanical strength of the rotor, and the influence of temperature on the deformation and stress of the rotor is explored. Through the analysis, it is found that the slot matching scheme has a great influence on the torque ripple of the motor, and the torque ripple can be reduced by selecting the slot matching scheme reasonably. Secondly, the size of the rotor slot has a great impact on the electromagnetic and mechanical properties of the motor, and it is necessary to comprehensively consider and jointly optimize its size.

Dynamic Decoupled Current Control for Smooth Torque of the Open-Winding Variable Flux Reluctance Motor Using Integrated Torque Harmonic Extended State Observer

Variable Flux Reluctance Machines (VFRMs) face multiple interconnected challenges that limit their performance, particularly in high-performance applications such as electric vehicles (EVs), where smooth torque output and robust operation are critical. Chief among these challenges are complex inter-axis couplings, including cross-coupling in the dq-axis, differential term coupling in the d0-axis, and disturbances propagating from the 0-axis to the q-axis. Additionally, harmonic disturbances associated with torque ripple exacerbate performance issues, resulting in degraded dynamic behavior. These challenges hinder current loop controllers, preventing effective management of winding impedance voltage drops and inter-axis coupling terms without advanced decoupling strategies. To address these challenges, this paper proposes a novel integrated torque harmonic extended state observer (ITHESO) within a decoupled current control designed to ensure fast and accurate current tracking, system stability, and torque ripple reduction. The ITHESO identifies and compensates for total current disturbances, including harmonic components, through feed-forward compensation within the current loop. Furthermore, the influence of control parameters and the effects of parameter mismatches on stability, torque ripple reduction, and disturbance rejection are thoroughly analyzed. Experimental validations demonstrate that the proposed strategy significantly enhances torque dynamics and reduces torque ripple, outperforming the conventional Active Disturbance Rejection Control (ADRC), which does not explicitly address disturbances associated with torque ripple. These advancements position the VFRM with the ITHESO as a competitive option for high-performance EV propulsion systems, offering smooth operation, noise reduction, and reliable performance under varying speeds and loads.

Performance Comparison of Permanent Magnet Synchronous Motor with Different Magnet Configuration Used in Electric Vehicle

Due to the depletion of fossil fuels, increasing environmental pollution, and global warming, the use of electric vehicles is becoming more widespread. Electric vehicles offer numerous advantages, including high efficiency, quiet and vibration-free operation, and being environmentally friendly. Electric motors provide high power density and a wide torque-speed range. Therefore, many engineering studies, analyses, and comparisons are conducted for electric motors used in electric vehicles. In this study, modeling and analyses of interior permanent magnet synchronous motors with different magnet configurations were carried out, taking as a reference an interior permanent magnet synchronous motor used in a mass-produced and well-selling electric vehicle. At the end of the study, structures with different magnet configurations were compared in terms of performance characteristics such as torque, torque ripple, and efficiency.

ANFIS-Based Resonant Controller for Mitigating Torque Ripples and Addressing Parametric Variation in PMSM-Driven Electric Vehicle

ANFIS-Based Resonant Controller for Mitigating Torque Ripples and Addressing Parametric Variation in PMSM-Driven Electric Vehicle

Stabilisation for multi-phase switched reluctance machine by a novel synchronisation of harmonic eradication mechanisms without resistance measurement and input-output relationships

This paper concentrates on dealing with two problems of 8/6-type Multi-phase Switched Reluctance Machines (MSRMs). Two problems are the stabilisation of rotational speed and minimising the output torque ripple for this machine. For the first issue, the output torque of 8/6 MSRMs is stabilised by determining an optimal holding time for the switching process. Minimising the total output torque ripple facilitates the 8/6 MSRMs operating more smoothly and counteracts the mechanical vibrations. For the second issue, this paper proposed a new synchronisation of high-order harmonic eradication mechanisms (HF-HEM) based on the Radial Basis Function (RBF) neural network and a hyperbolic-secant-like-function hierarchical method. The proposed scheme not only eliminates the high-frequency harmonics but also stabilises the rotational speed of 8/6 MSRMs at the desired values. Finally, the mathematical analyses are given by theorems. All the stable performance and impressive effectiveness of the proposals will be validated in the simulation section.

Effect of center-offset arc pole shoe shapes on torque ripple and eddy-current loss of consequent pole rotor

Effect of center-offset arc pole shoe shapes on torque ripple and eddy-current loss of consequent pole rotor

Optimization of the DTC control for doubly-fed induction motor using a PID based-genetic algorithm: Experimental validation on the dSPACE 1104 board

This article presents a very interesting approach to Direct Torque Control (DTC) for a doubly-fed induction motor utilizing two voltage-source inverters. The speed control of this system is achieved using a proportional-integral-derivative (PID) controller optimized by a genetic algorithm. Although the conventional DTC method offers many advantages, such as effective and dynamic control, robustness, ease of use, and impressive results, it also has drawbacks, including fluctuations in electromagnetic torque and variable switching frequencies, which lead to vibrations and accelerated aging of the machine. The purpose of this article is to improve torque control based on the direct method (DTC) and to address these limitations. To achieve this, a new control strategy called Genetic Algorithm-based DTC (GA-DTC) is proposed. This strategy integrates the optimized PID controller and is implemented across the entire operational range of the system. The entire system is validated using the MATLAB/Simulink environment to analyze the machine’s characteristics, its transient behavior, and its performance in steady state. This integration leads to a notable improvement in the machine’s performance, particularly in tracking speed and torque set points, reducing response times, and decreasing overshoot. Experimental validation is carried out using a 1.5 kW rotating electrical machine (DFIM-DCM) connected to a resistive load. The experiments are conducted using the DSPACE DS1104 experimental system, and the system’s behavior is tested under various operating conditions. The results obtained show the evolution of speed, torque, as well as stator and rotor currents. According to these results, the motor’s performance has been improved: response time has decreased, settling time has increased, and torque ripple has been reduced.

Variable Conduction Mode Control Method to Reduce Torque Ripple for Symmetrical Winding Multiphase Brushless DC Motor

Variable Conduction Mode Control Method to Reduce Torque Ripple for Symmetrical Winding Multiphase Brushless DC Motor

Torque ripple suppression for fault-tolerant motor under open-circuit condition based on PIR controller

Torque ripple suppression for fault-tolerant motor under open-circuit condition based on PIR controller

Torque Ripple Mitigation in Sensorless PMBLDC Motor Drive With Adaptive Observer for LEV

Torque Ripple Mitigation in Sensorless PMBLDC Motor Drive With Adaptive Observer for LEV

Development of a Radial-Flux Machine With Multi-Shaped Magnet Rotor and Non-Ferromagnetic Yoke for Low Torque Ripple and Rotor Mass

Development of a Radial-Flux Machine With Multi-Shaped Magnet Rotor and Non-Ferromagnetic Yoke for Low Torque Ripple and Rotor Mass

Intelligent Bearing Fault Diagnosis of Switched Reluctance Motor Using Hilbert-Huang Transformation and Region-Based Convolutional Neural Network

With the widespread trend of transportation electrification, much research has been focused on switched reluctance motor (SRM) because of its robustness and wide speed range. Though the SRM has a promising electric fault tolerance, the rotor support bearings subjected to mechanical friction are vulnerable to brinelling and corrosion. Furthermore, traditional bearing fault diagnosis approaches adopted for conventional motors are not well suited for SRM bearings because of its high torque ripples and noisy operation. Aiming at offering an efficient solution, this work proposes a novel technique by fusing the Hilbert-Huang transformation of vibration signal with region based Convolutional Neural Network. The core idea of the method is to decompose the vibration signal and employ a new kind of offline region generation algorithm for the detection of fault characteristics. The effectiveness of the designed model is tested and evaluated by a series of experiments. The results show that the proposed method achieved a remarkable diagnosis accuracy of 99.6%. Conclusively, a systematic comparison of the proposed model with the other state of the art models is carried out.

Direct torque control using SVM strategy of doubly fed induction generator

This article proposes direct torque control using space vector modulation DTC-SVM. This control strategy is preferred over other solutions, to guarantee performance and reduce torque and flux ripples. In order to better illustrate the effect of C-DTC and DTC-SVM control on the power quality, a spectral analysis of the stator currents THD has been carried out. The simulation results of the proposed controllers are compared for torque changes and flux. It is shown that DTC-SVM has several characteristics, such as simple algorithm, good dynamic response, constant switching frequency. The results proved excellent performance and verify the validity of the proposed system. The behavior of the proposed DTC-SVM scheme is fully verified using Matlab/Simulink software.

Sensitivity Analysis of MTPA Control to Angle Errors for Synchronous Reluctance Machines

This study investigated the sensitivity of maximum torque per ampere (MTPA) control in synchronous reluctance machines (SynRMs) to angle errors, examining specifically how deviations in the reference control trajectory affected performance. Analytical and numerical methods were employed to analyze this sensitivity systematically, including the impact of magnetic saturation. Two MTPA control implementation schemes were evaluated, with torque and current amplitude as the reference variables, using a template SynRM from the open-source simulation tool SyR-e. The results indicated that performance sensitivity to angle errors was moderately low near the MTPA trajectory, allowing for significant angle deviations with minimal performance loss. Although magnetic saturation increased this sensitivity slightly, reducing the allowable error range by up to 25%, the maximum angle deviation for up to 1% of the performance decrease still corresponded to approximately ±3∘ around the MTPA trajectory. The findings of this study suggest potential for simplifying control implementations, reducing component costs through less precise position determination (sensor-based or sensorless), and achieving additional control objectives such as torque ripple reduction.

PERFORMANCE COMPARISON OF WINDING TYPES AND ROTOR STRUCTURE IN SYNCHRONOUS RELUCTANCE MOTOR

Synchronous Reluctance Motors (SynRMs) have attracted a lot of attention in recent years due to their simple construction, high efficiency and the fact that they do not require rare earth magnets. SynRMs produce torque by directing the magnetic flux through barriers in the rotor, making them a low-cost alternative. The performance of the motor can vary significantly depending on the design of the stator windings and rotor barriers. Different combinations of stator winding types and the number of rotor barriers directly affect the critical performance parameters of the motor such as torque, efficiency, torque ripple, output power, saliency ratio and copper consumption. In this study, SynRMs using six different stator winding types and two different rotor barrier structures (3 and 4 barriers) are analyzed. Output power, efficiency, torque, torque ripple, saliency ratio, d-q axis inductances depending on current phase angle, total losses and copper consumption are investigated. The effect of full pitch and shortened pitch configurations in winding structures on the performance is discussed comparatively. The effect of 3 and 4 barrier rotors on these parameters is also evaluated. These analyses aim to reveal the ways in which winding and rotor configurations in motor design can be used to optimize performance. SynRMs can provide energy efficiency and cost benefits in a variety of industrial applications, therefore selecting the proper configuration is of great importance from both an economic and performance perspective.

EFFECTS OF ASYMMETRICAL STATOR STRUCTURE ON BLDC MOTOR PERFORMANCE FOR HOUSEHOLD APPLIANCES

Brushless direct current motors (BLDCM) have been frequently preferred in the industry, especially in home appliances, due to their advantages such as long life, high efficiency, low maintenance costs and ease of control. In addition to these advantages, the main disadvantages of these motors are known to be high torque ripple and vibration levels. In this study, alternative asymmetric designs are realized in the stator tooth structure of the BLDCM designed for home appliances, and comparative analyses of the effects of the non-uniform air gap caused by the asymmetric tooth structure on the motor performance are presented. Two different asymmetric structures, namely the model with clockwise asymmetric design (CW) and the model with counterclockwise asymmetric design (CCW) in the stator tooth structure, are determined in the stator design. With these alternative designs, improvements are made in terms of torque ripple and cogging torque when compared with the reference motor; notably, the CCW-2 model achieves the lowest ripple at 19.4% compared to 23.1% for the reference motor, and a 42% reduction in cogging torque. The design of the motor models is made in ANSYS EDT program as two dimensional (2D) and analyzed with the Finite Element Method (FEM). In the analysis results, air gap flux density, torque, torque ripple and cogging torque are examined, and the flux density and torque spectrum obtained by Fast Fourier Transform (FFT) are presented comparatively