In-wheel Switched Reluctance Motor Research Articles

Fault-tolerant control of in-wheel switched reluctance motor drive systems for vehicles under regenerative braking condition

Fault-tolerant control of in-wheel switched reluctance motor drive systems for vehicles under regenerative braking condition

Comparative assessment of a novel 8/18 multi-teeth with conventional 8/10 in-wheel SRM for an E-Scooter

Electric scooters are increasingly gaining popularity in India owing to rising global crude oil prices and rising levels of vehicular pollution. Most of them are currently powered by expensive in-wheel (IW) permanent magnet (PM) brushless DC motors. Owing to their simplicity, and ruggedness while being cost-effective (since they do not employ PMs), switched reluctance motors (SRMs) are a viable alternative. Despite these benefits, SRMs possess drawbacks such as low torque density and inferior efficiency. Recently, a multi-teeth (MT) SRM with an improved performance was reported. However, the design of MTSRM topologies and their electromagnetic performance have not been explored sufficiently. In this paper, a design formula governing the selection of the number of MT and rotor poles for MTSRMs has been proposed. Using this, a novel four-phase 8/18 IW-MTSRM is derived and proposed for an E-scooter. The characteristics of the proposed SRM are numerically compared with a conventional 8/10 SRM based on magnetic characteristics, efficiencies and steady-state operation for the complete torque-speed range. Results indicate that the proposed 8/18 MTSRM has a higher peak torque capacity, torque density, superior drive cycle efficiency and reduced torque ripple. Further, the FEA model is validated experimentally on a downsized 8/18 MTSRM prototype.

PEM fuel cell and supercapacitor hybrid power system for four in-wheel switched reluctance motors drive EV using geographic information system

In recent years, Electric Vehicles (EVs) powered by a Proton Exchange Membrane Fuel Cell (PEMFC) which has high energy density and efficiency have become an attractive solution for the automotive industry. However, since the power density of the PEMFC is not high enough for different road conditions such as accelerating and going uphill, a supercapacitor (SC) is preferred as the auxiliary energy source for high power density in EVs. Thus, in this paper, a hybrid power system consisting of the Fuel Cell (FC) and SC for a Four-Wheel Drive Electric Vehicle (4WDEV) is proposed. Since energy requirement of the EV depends on the travel route, an effective Energy Management System can be designed by using a Geographic Information System (GIS). According to the road trajectory, the power requirement of the EV is estimated and thus, energy consumption is reduced. The proposed system is validated by using the Matlab Simscape Toolbox.

Negative dynamics effect of in-wheel switched reluctance motor with inclined airgap eccentricity on handing stability for electric vehicle

This paper focuses on the negative effect of in-wheel switched reluctance motor (SRM) with inclined airgap eccentricity for the handling stability of electric vehicle (EV). Firstly, the radial electromagnetic force of the SRM under inclined airgap eccentricity is deduced based on the Maxwell stress tensor and airgap permeability correction coefficient, and the calculation results are verified by the built measurement device. Then, a dynamics model of in-wheel motor driving EV is constructed according to the response relationship of driving wheels. Finally, the influence of unbalanced radial torque (URT) on the negative dynamic effect of EV is analyzed with angular step input and sine input respectively. The simulation results show that the EV will deviate from the expected trajectory due to the impact of URT, which will threaten driving safety in vehicle steering or overtaking. In addition, the vehicle yaw velocity will deteriorate with the increase of the driving speed and turning angle, which will affect the dynamics response of vehicle handling stability. This research, starting from the coupling relationship between in-wheel motor response characteristics and vehicle driving conditions, can provide theoretical support for the popularization and application for in-wheel motor driving EVs.

Wireless Power Transmission-Based In-Wheel Switched Reluctance Motor Drive System With an x-Type Converter

This paper proposes a wireless power transmission (WPT)-based in-wheel switched reluctance motor (IWSRM) drive system, which uses an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x-</i> type converter at the motor side with charging function. In this system, a single frequency WPT subsystem with one transmitter coil and one receiver coil is used to completely isolate the DC power side from the motor side, and realize a transmission voltage gain of 1 by incorporating the symmetrical LCC-S network, which has the advantage of constant voltage gain when load changes. Be different from asymmetric half-bridge (AHB) converter, at the motor side an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x-</i> type converter with minimum number of active power switches is employed to connect the WPT subsystem, in which one power switch and one diode are used for each phase with independent control. The number of power active devices are reduced by half compared to AHB converter. Two freewheeling modes are analyzed for the drive system: the resistance freewheeling mode and the battery charging freewheeling mode. An experimental setup for a WPT-based three-phase 18/24-pole IWSRM system was built and tested. The simulation and experiment results of the system under two freewheeling modes are presented to validate the analysis and effectiveness of the system. The DC-to-DC efficiency is achieved over 96% with 100 mm air gap and the system efficiency is achieved up to 82% with the battery charging freewheeling mode.

Mechanism analysis and optimum control of negative airgap eccentricity effect for in-wheel switched reluctance motor driving system

In this paper, the generation mechanism of the negative airgap eccentricity effect for the in-wheel switched reluctance motor (SRM) driving system is analyzed. An independent current chopping control strategy is proposed to achieve optimum control between the response characteristic of the in-wheel motor driving system and the dynamic performance of electric vehicle (EV). Firstly, the electromagnetic characteristic of the studied SRM under airgap eccentricity is studied based on electromagnetic coupling model and circuit driving equation, and the radial electromagnetic force under different airgap eccentricity is verified by adopting the built experiment device. Then, combined with the excitation characteristics of the radial electromagnetic force, the negative dynamic effect of the in-wheel motor driving system is analyzed in the time–frequency domain. Finally, an independent current chopping control strategy for the in-wheel SRM driving system based on vehicle vibration feedback is proposed. The controller parameters including the turn-off angle and chopping current threshold are optimized by data interpolation. Results show that the proposed control strategy can achieve the optimum control between the response characteristics of the in-wheel motor driving system and the vehicle dynamic performance, especially to suppress the vehicle sprung mass acceleration and tire bounce while starting EV.

Investigation of an Outer Rotor In-Wheel Switched Reluctance Motor for Electric Vehicles by Finite Element Method

The demand of fossil fuel vehicles has decreased due to carbon emissions. Recently, electric vehicles (EV) with electric motor propulsion have gotten attention due to their zero carbon emissions and high efficiency. In this study, an outer rotor in wheel switched reluctance motor (IWSRM) with 18 poles on the stator and 24 poles on the rotor, designed for the propulsion of electric vehicles, is investigated in two-dimensional Finite Element Method (FEM). The magnetic field distributions of IWSRM for different rotor positions at nominal current are obtained. Then, the torque and phase inductance are calculated. As a result, the designed IWRSM provided low torque.

Experimental investigation of modified in-wheel switched reluctance motor with reduced torque ripple for electric vehicles

This research work is aimed at the modification of in-wheel switched reluctance motor (Outer rotor-type SRM) with minimized torque ripple for electric vehicles. The geometry of stator and rotor poles affects the torque. Variation in the stator and rotor pole geometry causes change in the torque profile. To reduce the torque ripple and to increase the average torque, modification in the stator and rotor pole shoes is presented in this article. The stator and rotor pole shoes with notches and projections are proposed with the objective of minimization of torque ripple and maximization of average torque. Electromagnetic analysis of conventional and modified in-wheel SRM is done with computer-aided design software MagNet 7.1.1. From the finite element analysis results, the average torque and torque ripple values are derived. Prototype of 8/6, 1000 W in-wheel SRM with the notches and projections is fabricated. Experimentation is performed on the fabricated machine to measure the magnetic flux linkage, current and speed characteristics of the proposed in-wheel SRM. The precise determination of magnetic flux characteristics is significant to check the machine design and to accurately predict the action of modified in-wheel SRM. Static modeling results of the fabricated machine were coherent with the experimental values.

Vibration Control for Electric Vehicles With In-Wheel Switched Reluctance Motor Drive System

The in-wheel switched reluctance motor (IWSRM) has significant potential for utilization in electric vehicle (EV) because of its inherent advantages such as low cost, robustness, wide speed range, and direct drive mode. However, the unbalanced radial force caused by eccentricity of IWSRM results in increasing vehicle vibration and decreasing riding comfort. In this paper, various vertical vibration control strategies for IWSRM are proposed and compared to improve the vibratory behavior of vehicle. First, effects of eccentricity ratio and eccentric angle on radial force, torque, and inductance are investigated by numerical analysis method for IWSRM. Then, IWSRM model, vehicle model, and suspension model are developed, based on which two common control algorithms (i.e. CCC and PWM) are provided and used as benchmarks to compare with the newly proposed two (i.e. CCC-F and PWM-F). They are designed by introducing the vehicle vertical acceleration as an extra control objective. Finally, the dynamic response of four control strategies are analyzed and the comparison results show that each of them performs differently under different driving conditions. As a result, a switchable controller based on the proposed control algorithms is presented to improve the overall performance of the IWSRM for EVs under various driving modes.

Investigation of optimal control for vibration and noise reduction in-wheel switched reluctance motor used in electric vehicle

In this paper, an appropriate control technique is investigated to reduce vibration and noise in switched reluctance motors (SRM). Vibrations are mainly caused by radial force acting on salient poles of the motor. In order to determine this force, a no linear model for switched reluctance motor is developed, based on finite element calculation of inductance and natural frequencies of stator. Thus, the force component at a frequency close to natural frequency of stator should be reduced. In this context, a method of two steps commutation is also applied. To verify the effectiveness of the proposed method, the electro-mechanical-acoustic developed model makes possible to define theoretical spectrum of vibration and noise with conventional and proposed method. The simulation results showed that the proposed method performs better in terms of vibration and noise reduction.

Coupling effect between road excitation and an in-wheel switched reluctance motor on vehicle ride comfort and active suspension control

The coupling effect between road excitation and an in-wheel switched reluctance motor (SRM) on vehicle ride comfort is numerically analysed. A hybrid control system consisting of fault tolerant H∞ suspension controller and SRM controller for an in-wheel SRM driven electric vehicle is proposed to improve the vehicle ride comfort and motor operation performance. By conducting numerical simulations based on the developed quarter-car active suspension model and switched reluctance motor model, it is observed that the road roughness is highly coupled with SRM airgap eccentricity and unbalanced residual vertical force. The SRM airgap eccentricity is influenced by the road excitation and becomes time-varying such that a residual unbalanced radial force is induced; which is one of the major causes of SRM vibration. To suppress SRM vibration and to prolong the SRM lifespan, while at the same time improving vehicle ride comfort, a fault tolerant controller based on output feedback H∞ control method is designed to reduce the sprung mass acceleration. Moreover, an SRM controller is adapted by using the combined Current Chopping Control (CCC) and Pulse Width Modulation control (PWM) to further improve the SRM performance. A comparison of passive suspension and suspensions with hybrid control method on the vehicle and SRM dynamic response under stochastic road excitation and bump road excitation is illustrated. The results indicate that the proposed hybrid control method can effectively reduce the SRM airgap eccentricity, residual unbalanced radial force and achieve better vehicle ride comfort.

Design and optimisation of an In‐wheel switched reluctance motor for electric vehicles

To improve the mechanical performance of the In-wheel switched reluctance motor (SRM) used in electric vehicles (EVs), structure design and geometrical multi-objective optimisation strategy for the In-wheel SRM were developed in this study. The design method for major parameters of the In-wheel SRM was presented by means of design specifications of the EVs. According to requirements of the EVs, four indicators of the SRM were defined to evaluate the development of the SRM and perform the optimisation. To simultaneously improve the static performance of the SRM, a novel multi-objective simultaneous optimisation function was proposed by using four weighted factors and considering sensitivity analysis of the design variables on indicators. A four-phase 16/20 In-wheel SRM with an outer rotor was designed and optimised based on the proposed multi-objective optimisation method. The influence of design variables on average torque, torque ripple, efficiency, and torque density was analysed based on a combination of finite element analysis and orthogonal experiment design method. The static and dynamic torque performances of the optimised SRM were evaluated and compared with those of the initial motor. The comparison results showed that the proposed multi-objective simultaneous optimisation strategy can greatly improve the static and dynamic torque performances of the SRM.

Simultaneous Optimization of Geometry and Firing Angles for In-Wheel Switched Reluctance Motor Drive

Interests in using rare-earth free motors such as switched reluctance motors (SRMs) for electric and hybrid electric vehicles continue to gain popularity, owing to their low cost and robustness. Optimal design of an SRM, to meet specific characteristics for an application, should involve simultaneous optimization of the motor geometry and control in order to achieve the highest performance with the lowest cost. This paper presents a constrained multiobjective optimization framework for design and control of an SRM based on a nondominated sorting genetic algorithm II. The proposed methodology optimizes SRM operation for high volume traction applications by considering multiple criteria including efficiency, average torque, and torque ripple. Several constraints are defined by the considered application, such as the motor stack length, outer diameter, minimum operating power, minimum desired efficiency, rated speed, rated current, and supply voltage. The outcome of this optimization includes an optimal geometry, outlining variables such as air gap length, rotor inner diameter, stator pole arc angle, rotor pole arc angle, rotor back iron, stator pole height, and stator inner diameter as well as optimal turn-on and turn-off firing angles. Then the machine is manufactured according to the obtained optimal specifications. Comprehensive finite-element analysis and experimental results are provided to validate the theoretical findings.

Vibration mitigation for in-wheel switched reluctance motor driven electric vehicle with dynamic vibration absorbing structures

This paper presents a new approach for vibration mitigation based on a dynamic vibration absorbing structure (DVAS) for electric vehicles (EVs) that use in-wheel switched reluctance motors (SRMs). The proposed approach aims to alleviate the negative effects of vibration caused by the unbalanced electromagnetic force (UMEF) that arises from road excitations. The analytical model of SRMs is first formulated using Fourier series, and then a model of the coupled longitudinal-vertical dynamics is developed taking into consideration the external excitations consisting of the aerodynamic drag force and road unevenness. In addition, numerical simulations for a conventional SRM-suspension system and two novel DVASs are carried out for varying road levels specified by ISO standards and vehicle velocities. The results of the comparison reveal that a 35% improvement in ride comfort, 30% improvement of road handling, and 68% improvement in air gap between rotor and stator can be achieved by adopting the novel DVAS compared to the conventional SRM-suspension system. Finally, multi-body simulation (MBS) is performed using LMS Motion to validate the feasibility of the proposed DVAS. Analysis of the results shows that the proposed method can augment the effective application of SRMs in EVs.

INFLUENCE OF STATOR EMBRACE ON TORQUE OF IN-WHEEL SWITCHED RELUCTANCE MOTOR

In this paper, influence of stator pole embrace on torque of In-Wheel Switched Reluctance Motor (IW-SRM) is investigated by numerical modeling based on Finite Element Method (FEM). For this reason, 3D numerical model of IW-SRM is built by using Ansys Maxwell Software Package. IW-SRM is analyzed and output torque and magnetic flux density of the IW-SRM are calculated. The analysis of IW-SRM is realized for different stator pole embraces and the results of the output torque and magnetic flux density of IW-SRM taken for various stator pole embraces are compared with each other. As seen from the results, when the value of stator pole embrace reduces, the output torque of IW-SRM increases. As a result in this study, the effects of different stator pole embraces are examined on the output torque of IW-SRM.

Design of a New Enhanced Torque In-Wheel Switched Reluctance Motor With Divided Teeth for Electric Vehicles

This paper presents a new switched reluctance motor (SRM) with wide speed range for the application of electric vehicles. It has an in-wheel structure for direct drive and multiple teeth per stator pole to enhance output torque. Also, the number of rotor poles is more than that of stator teeth. A 6/16 three-phase in-wheel SRM with the concepts of multi-teeth per stator pole and more rotor poles than stator teeth has been proposed for analysis. The torque performance of the topology with multi-teeth per stator pole is proven by theoretical analysis. Moreover, a new design formula is introduced for a novel combination of stator and rotor poles. The parameters of the motor are optimized by genetic algorithm method for the maximum torque output. Then the torque performance is computed by finite-element method (FEM) and compared with its counterparts, including three-phase 6/8 and 6/10 SRMs. The FEM results exhibit higher torque density for the proposed topology.

In-Wheel Switched Reluctance Motor Design for Electric Vehicles by Using a Pareto-Based Multiobjective Differential Evolution Algorithm

In this paper, an in-wheel switched reluctance motor (IW-SRM) is designed by using a Pareto-based multiobjective differential evolution algorithm (PMODEA) for electric vehicles (EVs). The performance of the IW-SRM varies by the dimension parameters of the motor. Estimation of optimum motor dimensions is a multiobjective optimization problem. In dimension optimization of the IW-SRM for direct-driven EVs, torque, torque per motor lamination volume, and efficiency are specified as objective functions. The PMODEA is proposed for the solution of the multiobjective optimization problem as designing IW-SRM, and nondominant optimum solution set consisting of motor dimensions is obtained. This study provides flexibility to the decision maker, in selection of desired one from the existing solution set. The analysis of the selected motor is realized by considering optimum dimensions via the finite-element method (FEM). Then, the IW-SRM is manufactured, and then, the experimental results are obtained for static and dynamic analysis. FEM analysis results are compared with the experimental results. Eventually, it is observed that the results are satisfactory.

Design, analysis, and control of in-wheel switched reluctance motor for electric vehicles

Estimation of dimension parameters for an electric machine has great importance before assembling on production line. As a matter of fact, researchers should find optimum solution once they decide to perform analytical design of an electric machine. In this study, we have tried to find dimensional and electrical parameters via derived mathematical equations for in-wheel switched reluctance motor (IW-SRM), and the motor has been manufactured. Moreover, an experimental setup is designed, and the speed and torque control of IW-SRM is carried out. The motor tests including both standstill and running test are performed by using the experimental setup. Initial size parameters are intuitively provided as motor analysis is conducted by software package. Then, numerous trials are examined to get optimum results. In fact, this motor is employed by an electric vehicle whose design is ongoing. Therefore, optimum motor parameters for required base speed and torque have been estimated by solving generated equations for IW-SRM with 18/12 poles via MATLAB. Considering parameters estimated, analysis of IW-SRM has been performed by Ansoft Maxwell 15.0 Software Package based on 3D finite element method (3D-FEM). Consequently, the estimated parameters have been validated by the results of Maxwell 3D FEM. Experimental results of the motor manufactured are obtained via the motor driver designed; also have been validated by Maxwell 3D.

Design of In-Wheel Type Switched Reluctance Motor for Electric Vehicle Traction and Wireless Charging

Design of In-Wheel Type Switched Reluctance Motor for Electric Vehicle Traction and Wireless Charging

Electric vehicles with in-wheel switched reluctance motors: Coupling effects between road excitation and the unbalanced radial force

The switched reluctance motor (SRM) has great application potential in in-wheel motor electric vehicle (IWM-EV) due to its advantages, such as a high starting torque for initial acceleration, a wide operating speed range and high efficiency to extend the battery service life. However, these advantages are overshadowed by its inherent vibration and noise due to the unbalanced radial force. For the vehicle vibration system, the vertical component of SRM unbalanced radial force, namely SRM vertical force, is one of the major concerns. This paper analytically investigates the coupling effect of SRM vertical force and road excitation on IWM-EV vibration. First, the system dynamics model of IWM-EV and IWM driving EV controller are proposed to include SRM vertical force; then the analytical models are solved to predict the vehicle dynamic responses at different speeds on periodic and stochastic road inputs with various amplitudes and coherence functions between left- and right-sides of the vehicle. It is concluded that SRM vertical force is highly coupled with road excitation and SRM airgap eccentricity, and such coupling effects yield a great impact on vehicle vertical vibration dynamics.