Torque Ripple Reduction Research Articles

A quick demagnetization approach for low torque ripple in three‐phase switched reluctance motor drive system for electric vehicle applications

SummaryElectric vehicles (EVs) have gained a forward approach for achieving the low carbon economy and green transportation. Switched reluctance (SR) motor‐based propulsion mechanisms have been popularly used for EVs due to the wide speed range capability. The conventional phase current regulation technique does not give the satisfactory reduction of torque ripple in SR motor drive, particularly for automotive applications. To overcome the issue, a frontend boost converter (FEBC) is proposed to realize the quick excitation and demagnetization. Initially, the problems associated with the conventional asymmetric half bridge converter are investigated at various levels of phase current. The various operating modes of proposed drive system with FEBC are explained in detail. The proposed FEBC has the significant benefit of being able to provide variable boosting voltages based on the dynamic behavior of the SR motor. The phase voltages are increased during the fast magnetization and demagnetization modes due to the inclusion of FEBC, and hence, quick magnetization and demagnetization have been achieved. The proposed FEBC drive system has been simulated through the Matlab Simulink toolbox. The experimental results are also carried out in order to validate the simulation results.

A Comparative Study on the Performance of the Induction Motor with Fuzzy-Based Power Converters

This study investigates the influence of load conditions on grid voltage stability and the performance of a proposed compensator, encompassing a 1.5 hp 4-pole induction motor (IM) exposed to grid voltage disturbances. Through rigorous grid current analysis, our research demonstrates the effective mitigation of total harmonic distortion (THD) without necessitating passive filters. The comprehensive study covers multiple facets, including control strategy optimization, fine-tuning of control parameters, component ratings, output voltage analysis, operating principles, pulse width modulation, and the integral role of the fuzzy logic controller. Specifically, it underscores the significant impact of a Predictive Torque Control-based Diode Clamped Inverter in enhancing the dynamic and steady-state performance of the IM. The research delves into traditional PTC control methods and advanced techniques, such as fuzzy and evolutionary control, addressing the persistent challenge of reducing torque ripple under varying load conditions. By implementing model prediction control-based DCI, our method achieves rapid torque response without compromising the motor’s stator characteristics. Utilizing MATLAB’s environmental package, we thoroughly evaluate motor performance across diverse scenarios, encompassing stable, and rapid load changes. Despite inherent winding impedance challenges, our proposed approach consistently delivers satisfactory output responses, contributing to a more efficient, and resilient IM performance under diverse operating conditions.

Reduction of inappropriate principal features of the switched reluctance motor using sinusoidal rotor configuration

AbstractThis paper presents a comprehensive analysis, electromagnetic evaluation, and prototyping of a novel motor structure called the sinusoidal rotor switched reluctance motor. In this innovative design, a significant departure from the conventional switched reluctance motor is observed, as modifications are made to the rotor with the goal of reduction torque ripple and radial force characteristics. Importantly, despite these advancements, the proposed motor retains the weight and volume characteristics of the traditional, type. The key attributes of these motors have been thoroughly assessed using the three‐dimensional finite element method, complemented by a sensitivity analysis aimed at identifying the most optimal configuration within the proposed design. The findings reveal that the suggested structure successfully achieves a notable reduction in torque ripple and radial force when compared to the traditional counterpart, albeit with an expected reduction in average torque. These features render the new topology particularly well‐suited for applications that prioritise noise and vibration reduction. Furthermore, the effectiveness of the proposed topology is corroborated through experimental tests, providing empirical evidence of its advantages and potential for practical applications.

An Iterative Learning Based Direct Torque Control Strategy of DC-Biased Vernier Reluctance Machines for Torque Ripple Reduction

An Iterative Learning Based Direct Torque Control Strategy of DC-Biased Vernier Reluctance Machines for Torque Ripple Reduction

Optimal energy management strategy for dual-power coupling tractor based on the adaptive control technology.

Hybrid tractors (HT) are regarded as the efficient agricultural machine due to their energy conservation performance and faster torque response to deal with load fluctuations. However, the strategy to allocate the battery and fuel energy for demand power should be discussed. In this paper, an on-line management strategy of the HT is proposed to optimize the energy consumption of engine and motor and to reduce torque ripple for power units. A new architecture for replacing power shift and continuously variable transmission technology is proposed. Then, the modified equivalent consumption minimization strategy (ECMS) is used to optimize the torque distribution in which the equivalent factor is further calculated for the real-time process. Besides, the modification of ECMS in variable working conditions can effectively analyse the torque distribution between the motor and engine. The numerical test is implemented that the effectiveness of the proposed energy strategy is validated in plowing conditions. The consequences indicated that the proposed power distribution strategy can adaptively allocate the torque demand according to the fluctuation load. Comparing with the traditional rule-based strategy, the proposed strategy can reduce 6.2% of the energy, and decrease torque ripple with the proposed tractor architecture.

Model Predictive Control of Switched Reluctance Machines for Suppressing Torque and Source Current Ripples Under Bus Voltage Fluctuation

This article presents a novel model predictive method for torque ripple and source current ripple suppression in switched reluctance machines (SRMs) when the bus voltage fluctuates. Based on the measured rotor position, phase current, and phase voltage, the states, including bus voltage, capacitor current, and phase flux-linkage, are calculated for the preparation of the prediction. On this basis, the machine torque and inverter current for all the possible switching states are predicted to construct the cost function. The operating state with the minimum value of cost function is considered as the optimal switch signal and applied to the control power converter, thus achieving the effect of simultaneous reduction of torque ripple and source current ripple. Experimental results show the proposed method has a significant effect on the suppression of both torque ripple and source current ripple even with bus voltage fluctuation, which verifies the effectiveness of the proposed method. The influence of the key factors, such prediction horizon, parametric variation, and weight coefficient, on the machine performance are further investigated. The proposed method is easy to be implemented in the control logic as well as robust to bus voltage fluctuations, enabling to promote the competitiveness of SRMs in electric vehicle application.

Enhanced Low-Speed Characteristics With Constant Switching Torque-Controller-Based DTC Technique of Five-Phase Induction Motor Drive With FOPI Control

The Classical hysteresis controller-based DTC (C-DTC) of an induction motor is a simple control scheme with better dynamics and steady-state characteristics when compared with the flux-oriented control (FOC) scheme. The major drawbacks of the C-DTC scheme are variable switching frequency and high average torque ripple under different rotor speeds. In this paper, the two-level five-leg inverter-controlled five-phase induction motor drive with constant switching torque controller-based DTC (PI-CST-DTC) scheme is introduced to improve the steady-state performance with constant switching frequency under various operating speeds. However, the proposed PI-CST-DTC exhibits slower torque and slower speed dynamics w.r.t C-DTC which is due to the periodic occurrence of zero vectors under transients. These slower dynamics are improved with the help of the proposed fractional order PI (FOPI) constant switching torque controller-based DTC (FOPI-CST-DTC) method. With the help of the hardware results, it has been verified that the proposed FOPI-based CST-DTC exhibits improved low-speed steady-state and dynamic performance of the five-phase induction motor drive. The proposed CST-DTC techniques with PI and FOPI controllers are compared with C-DTC for torque ripple reduction and %THD analysis and dynamics through hardware results.

Design Optimization Using Asymmetric Rotor in IPMSM for Torque Ripple Reduction Considering Forward and Reverse Directions

Design Optimization Using Asymmetric Rotor in IPMSM for Torque Ripple Reduction Considering Forward and Reverse Directions

High-Speed Design with Separated Tapering for Reducing Cogging Torque and Torque Ripple of a 3 kW Dry Vacuum Pump Motor for the ETCH Process

This paper proposes a design method to reduce cogging torque and torque ripple in the concentrated winding of IPMSMs (Interior Permanent Magnet Synchronous Motors) used in motors for the semiconductor ETCH process. IPMSMs can utilize reluctance torque through the difference in inductance between the d axis and q axis, but they are at a disadvantage in terms of reducing cogging torque while tapering the rotor and stator to reduce torque ripple. In addition, the existing single tapering can push the permanent magnets into the rotor. If the rotor’s permanent magnets are embedded, the magnetic reluctance will increase, and the overall performance of the motor will decrease. However, an optimum design method was derived in which the magnets do not move during rotor tapering. This geometric design is an optimum design method that reduces cogging torque and torque ripple. This paper compares and analyzes four models, the concentrated winding model, distributed winding model, conventional tapering model, and separated tapering model, using 2D and 3D finite element analysis (FEA).

Investigation of the impact of rotor shaping on the torque and radial force harmonics of a V‐shape interior permanent magnet synchronous machine

AbstractThis paper introduces a technique aimed at improving the performance of an interior permanent magnet synchronous machine (IPMSM) by reducing torque ripple and radial force harmonics. Unlike conventional IPMSMs, the proposed method employs a variable airgap length that is defined by a mathematical function. Two distinct rotor shapes are investigated to determine the most efficient design. Finite Element Analysis is employed to assess both the electromagnetic and mechanical attributes of the proposed motors. It compares the results for three operating points of the shaped motor with those of a conventional one. The investigation delves into the influence of rotor geometry on key output parameters, including Back Electromotive Force (back‐EMF) harmonics, average torque, cogging torque, torque ripple, efficiency, power factor, and radial force harmonics. The findings indicate that optimising rotor shape can significantly enhance IPMSM performance by reducing torque ripples and radial force harmonics, while simultaneously increasing average torque and efficiency at different operating points.

On winding reconstruction method for six-phase motor with single-phase winding open-circuit faults

Single-phase winding fault in six-phase permanent magnet synchronous motor (PMSM) will cause problems with reduced torque performance. For this problem, this paper analyses the reasons for the increase of torque ripple under single-phase winding open-circuit fault condition taking an 18-slot/10-pole (18S10P) six-phase surface mounted permanent magnet synchronous motor (SPMSM) as an example. Then, a torque performance improvement method by redistributing healthy phase windings to reconstruct the stator magnetic field is proposed in this paper. The proposed method not only can significantly reduce torque ripple caused by winding open-circuit faults but also can maintain a high average torque value. Moreover, this method is suitable for lots of six-phase motors with different pole-slot combinations. At last, considering the significant impact of harmonic contents in stator magnetic field on torque performance, an optimization method for armature current is proposed, which can decrease the torque ripple further. The simulation results by finite element analysis (FEA) show that the proposed method has significant superiority in motor fault operation.

Field Oriented Control Implementation on BLDC Motor Controller with PI and SVPWM using STM32F103C8T6

Brushless direct current (BLDC) motor are high power density motors with a wide scope for use in electric vehicles, home automation, and industry. But the motor performance degrades due to improper control actions. This is caused by uncontrolled BLDC motor torque currents. Field Oriented Control (FOC) method is a solution for controlling BLDC motor, because it has the advantaged of overcoming torque ripples at low speeds. This paper presents the implementation of FOC on BLDC motor using STM32F103C8T6, which is high speed and low cost microcontroller. STM32F103C8T6 has been applied to handle FOC algorithm calculation and data processing. In order to validate the FOC algorithm system and assess the performance of the STM32F103C8T6 microcontroller, a 350-watt BLDC motor on an electric bicycle was tested and compared with a Universal controller. The tests that have been conducted proven that the FOC controller makes power more efficient, rotates BLDC motor at low speeds, and reduces torque ripple.

Novel hybrid-MPCC approach to generate switching sequence for six-step commutation of BLDC motor using Hall effect sensor

This paper provided a novel control technique for generating a switching sequence for a six-step commutation of BLDC motor utilizing a Hall Effect sensor. The strategy combines hybrid control with a model predictive current control (MPCC), namely Hybrid-MPCC. The purpose of implementing Hybrid-MPCC is to obtain a simple commutation scheme, make step commutation works automatically, and reduces torque ripple. The framework of Hybrid-MPCC is a control system that is composed of an interacting continuous and discrete system that influences each other's behavior, kept the constant of the non-commutation phase current, predicted the phase current based on the output phase currents over a specified interval, controlled the three-phase currents separately by varying the motor speed and set the active PWM modulation. Desired properties of Hybrid-MPCC include global asymptotic stability of an equilibrium point and the close-loop system takes on safe values variables. The simulation and practical findings show that the proposed unique method in this work may successfully decrease torque ripple when compared to classic driving methods.

Torque Ripple Reduction Strategy for Brushless DC Motor Based on Output Mode Reconstruction of Cuk Converter

Torque Ripple Reduction Strategy for Brushless DC Motor Based on Output Mode Reconstruction of Cuk Converter

Optimal Torque Sharing Function Control for Switched Reluctance Motors Based on Active Disturbance Rejection Controller

In this article, an optimal torque sharing function (TSF) control method incorporated with improved linear active disturbance rejection control (LADRC) and modified coyote optimization algorithm (MCOA) is introduced and applied in switched reluctance motors (SRMs). First, the piecewise TSF is employed to reduce the torque ripple, which exhibits little effects on the rate of current change and the current peak value. The improved linear extended state observer with the variable gain in speed controller using LADRC is designed to guarantee better antidisturbance ability and torque ripple reduction simultaneously. Then, the MCOA is introduced to automatically tune the parameters including the turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> angle, conduction angle, and coefficients for better comprehensive performances. Finally, comparisons among the conventional TSF with LADRC, the piecewise TSF with LADRC, and the proposed TSF with improved LADRC are conducted both in the simulations and experiments. The results indicate that the proposed method behaves best in aspects of torque ripple suppression and anti-interference ability among the three methods.

Optimization of coaxial magnetic gear and its application in wave power generation

The application of coaxial magnetic gear (CMG) in wave generator instead of traditional variable speed gearbox can effectively improve torque density and reduce torque ripple. Thus, the operation principle of CMG from the perspective of magnetic field modulation is firstly analyzed in this paper. Then the air gap magnetic fields induced by high-speed and low-speed rotors are studied. And the radial height, inner diameter angle, and outer diameter angle of the modulating pieces (MPs) are optimized by using the combination of response surface method (RSM) and particle swarm optimization (PSO) algorithm to improve the torque transmission capacity of CMG. The CMG is combined with the permanent magnet synchronous machine to get the magnetic-gear permanent magnet synchronous generator (MG-PMSG). The design feasibility of the MG-PMSG is verified from four aspects: static magnetic field analysis, no-load characteristics, load characteristics and load disturbance analysis.

Experimental Comparison of Robust Control Algorithms for Torque Ripple Reduction in Multiphase Induction Generators

This paper introduces robust nonlinear controller strategies for multiphase induction machines, aiming to enhance operational reliability under healthy and faulty conditions, including stator phase and converter leg openings. Due to the induction machine’s inherent nonlinearities and parameter variations, a robust control is required. The study evaluates the effectiveness of the sliding mode control with linear feedback and switched gains, the fuzzy proportional integral control, and their combined application in both healthy and faulty modes. The experimental assessment involves a symmetrical six-phase induction machine in generation mode, with comparisons with a classic proportional integral controller for inner current loop regulations. Experimental results show that the fuzzy proportional integral controller presents the best performance by minimizing torque ripples during both healthy and faulty operations.

Torque Ripple Reduction of Switched Reluctance Machine With Torque Distribution and Online Correction

In order to reduce the torque ripple of the switched reluctance machine, a new control strategy, characterized by online correction of the reference phase torque, is proposed based on the torque sharing function. First, the required total torque is distributed to each phase based on the cosine-type torque sharing function, and the real-time phase current is used to predict its maximum and minimum value that the machine can reach at the next control period. Then, the phase torque range can be obtained, which is applied to the online correction of the reference phase torque. The goal of the correction is to make the reference value of the phase torque within the torque range. Finally, the corrected reference torque is converted into reference current for current tracking, and the drive signal for the power converter can be generated. To evaluate the performances of the proposed control method, detailed simulation and experiment are carried out. The results indicate that compared to the traditional torque sharing function method, the proposed method can effectively reduce the torque ripple and enhance the efficiency simultaneously.

Electromagnetic Characteristics Analysis and Torque Ripple Reduction for Doubly Salient PM Machine

In this paper, the air-gap field modulation analysis and torque ripple reduction method for doubly salient permanent magnet motor (DSPMM) are presented. Based on the flux linkage distributions in the motor, the equivalent magnetic circuit models for permanent magnet (PM) and armature winding excitations are built, respectively. The air-gap magnetomotive forces (MMFs) caused by PM MMF and armature MMF can be obtained by combining the air-gap permeance and equivalent magnetic circuit models. The electromagnetic properties of the DSPMM are investigated from the perspective of air-gap field modulation principle. It is revealed that multiple field harmonics contribute to torque generation, and the torque ripples of the DSPMM are mainly caused by the cogging torque. To reduce the torque ripples, the 5th or 7th harmonic currents can be injected into the armature winding to compensate the cogging torque, and their analytical formulas will also be given. The finite element simulations and experiments are carried out to verify the results of theoretical analysis and the effectiveness of the proposed control method.

Torque Ripple Reduction of Nonsinusoidal Brushless DC Motor Based on Super-Twisting Sliding Mode Direct Power Control

In this paper, a second-order sliding mode control, based on super-twisting algorithm, is proposed for direct power control of the brushless DC (BLDC) motor. The proposed controller uses a super-twisting scheme that requires only sliding surface information and can handle system uncertainties and external disturbances, well. This scheme can improve the BLDC motor torque ripple by solving the disadvantages of the conventional sliding mode control method, such as the chattering effect and high frequency switching control. This method is simple and robust for the BLDC motor’s biggest challenge, torque ripple, which does not require any voltage and current control loops or complex reference frame transformations. The simulation results of the proposed method are compared with the direct power control (DPC) and model predictive control (MPC) methods, which indicate the superiority of the proposed method in both the steady- and transient-states. Moreover, the motor parameters variation in the tracking of active and reactive power are discussed. In addition, the practical results of the proposed method in both cases of speed and load variation show the effectiveness of this method in reducing power (torque) ripple and current total harmonic distortion (THD) and increasing the system’s efficiency compared to other methods.