Electric Vehicle Motor Research Articles

Speed Stability and Anti-Disturbance Performance Improvement of an Interior Permanent Magnet Synchronous Motor for Electric Vehicles

To enhance the speed stability and anti-interference performance of the interior permanent magnet synchronous motor (IPMSM) in electric vehicles, a composite control strategy, incorporating sliding mode control (SMC) and extended state observer (ESO), was implemented to regulate the IPMSM’s speed. Firstly, three simulation analysis models of the IPMSM were established based on its electrical parameters. The current-loop regulator was a PI regulator, while the speed-loop regulators consisted of a basic SMC regulator, a linear SMC–ESO regulator, and a nonlinear SMC–ESO regulator. The simulation analysis results demonstrated that all three speed-loop regulators effectively ensured the speed stability of the IPMSM. However, the nonlinear SMC–ESO regulator exhibited superior performance in terms of enhancing the IPMSM’s resistance to disturbances. Secondly, a hardware testing platform was constructed to validate the simulation analysis findings. The hardware testing results, when compared to the simulation analysis results, revealed the need for optimization of the PI regulator’s control parameters to maintain the speed stability of the IPMSM. Moreover, contrary to the simulation analysis results, the hardware testing results indicated minimal difference in the anti-disturbance performance of the IPMSM between the linear SMC–ESO regulator and the nonlinear SMC–ESO regulator. Finally, the differences between the simulation analysis results and the hardware testing results are thoroughly discussed and analyzed, providing valuable insights for the practical implementation of IPMSM in electric vehicle drive systems.

Speed regulation of electric vehicle motor based on PID control

Electric vehicles, as a new technological advancement in the automotive industry for addressing energy and environmental issues, have become a hot topic in both domestic and international car development. The electric vehicle generator, which plays a crucial role, is a key component of electric vehicles. The Alternating Current (AC) motor in electric vehicles is highly efficient and widely used in various fields. Therefore, studying AC motors holds significant theoretical and practical significance. This article first explains the car model and the principle of the electric motor, followed by an analysis of the ProportionalIntegralDerivative (PID) principle. Finally, through PID control, the simulation of the electric vehicle's speed is conducted to achieve better stability and economy. The experiments demonstrate that by improving the phase margin and stability of the lag compensator and feedback loop system, the driving comfort and practicality of electric vehicles can be effectively enhanced.

Analysis of torque controlling strategies of interior permanent magnet synchronous machine in hybrid electric vehicle

Significance of this research is based on torque controlling strategies in hybrid electric vehicle. The traction motor of a hybrid electric commercial vehicle must have a high power density-to-weight ratio and excellent torque at extremely low speeds. A proportional-integral controller estimates the high-resolution rotor position based on the difference between actual as well as reference output power. This technique can correct for hall position sensor installation error and also accurately estimate rotor position. In this study, a current proportional integral controller is also used to determine the permanent magnetic flux linkage. Experiments are used to test other key metrics such as d-axis and q-axis inductances, stator resistance, and energy loss. The measured parameters are kept in lookup tables that span the whole operating range at various current levels. A maximum torque per ampere control methodology, paired with the feed forward parameter iteration method, may be used to produce accurate and efficient torque control based on these precise parameters. The standard driving cycle performance requirements of the modelled Federal Test Procedure vehicle is analysed in the article for understanding the real model requirements of the vehicle. The efficacy of the proposed methodology using Matlab/Simulink environment is analysed. Both modelling and experimental findings validate the efficacy, torque ripple, stator and rotor flux, sensitivity of the vehicle parameter as well as the computational complexity of the proposed methodology.

Optimum design and research of switched reluctance motor for electric vehicle based on Motor-Cad

With the development of the economy and the deepening of the energy crisis, electric vehicle has now become the hotspot of the global automotive industry. Therefore, as the key part of electric vehicle, the design and research of drive motor has become the focus of attention of engineers and technicians. Because of its simple structure, easy maintenance, high output power, high output torque, wide speed range, and high efficiency, the switched reluctance motor (SRM) has been one of the first choice of electric vehicle driving motors. According to the performance requirements of electric vehicle driving motors, a 3-phase 24/16 pole with rated power of 30 kW switched reluctance motor (SRM) for electric vehicle has been designed in this paper by using Motor-Cad which can be used to optimize the parameters of motor to make the overall structure of the motor more reasonable. In order to reduce the torque ripple of switched reluctance motor, appropriate stator polar arc and rotor polar arc design are used in the motor. To realize the speed control of switched reluctance motor in a wide range, PWM control mode is adopted in this paper, which has fast motor response speed, high power factor and excellent dynamic and static performance. The simulation results show that the performance indexes of the switched reluctance motor meet the design requirements completely.

An Improved Method of Permanent-magnet Flux Observer for Interior Permanent Magnet Synchronous Motor Based on Adaptive Theory

Permanent magnet synchronous motor is often used as drive motors for electric vehicles. It is prone to demagnetization failure, and the change of permanent magnet flux link is an important basis for diagnosing demagnetization failure of the motor. First, the study establishes a permanent magnet flux adaptive observer and ensures its stability. Then the sensitivity analysis of the main parameters in the observer is carried out. For the parameter with high sensitivity and a large range of variation during motor operation, the expression of flux observation error caused by this parameter change is derived, and the gain matrix in the observation model is optimized. Through simulation verification, the observer can be used for the demagnetization fault diagnosis of the motor.

A Novel Magnetic-Geared Motor Combining Magnetic Gear and SR Motor

A direct-drive permanent magnet (PM) motor and a magnetic-geared PM motor have the advantage of high torque density. Therefore, these motors are expected to be applied as in-wheel motors for electric vehicles (EVs). However, they have a problem that it is difficult to achieve the wide speed-torque characteristics required for EVs. This paper presents a novel magnetic-geared motor that consists of a flux-modulated type magnetic gear and a switched reluctance (SR) motor. In this paper, the SR motor part and the magnetic gear part are designed, and both parts are combined into a magnetic-geared motor. The proposed magnetic-geared motor has the wide speed-torque characteristic, which direct-drive PM motors or SR motors cannot achieve.

Optimal placement criteria of actuators for hybrid mounting system on a non-aligned plate structure

Electric motors in electric and hybrid vehicles generate mid-frequency noise and vibration. These factors cause drivers to experience discomfort while traveling. Active mounting techniques have been extensively researched and developed to effectively address this issue. The optimal placement of an active mounting system is essential for enhancing NVH performance when an active mounting system is utilized. In order to propose optimal location criteria for active paths, this paper concentrates on developing an analytical model based on both dynamic and static analysis. The secondary forces along active trajectories are mathematically determined when a structure is subjected to an excitation force. These locations are considered optimal for the active mounting system if the secondary forces are comparatively minimal. Simulations and feasibility experiments are also conducted in order to validate the proposed method. In addition, the results are compared with the case of beam structure. It has been determined through this procedure that the active path’s control performance will be enhanced if it is positioned in the optimal location and less control force is required than in the case of beam.

Multi‐Objective Optimization and Analysis of Asymmetric Hybrid‐Magnet Offset Motor for Electric Vehicles

Aiming at the high cost of permanent magnet synchronous motor and the reduction of motor output performance caused by high cogging torque and torque ripple, an asymmetric hybrid‐magnet offset motor is proposed. Based on the winding function theory and the equivalent magnetic circuit method, the expressions of stator and rotor magnetic potential are derived respectively, and the analytical model of torque ripple is established by combining with the Lorentz force law. By using the magnetic pole offset method, the phase offset model of the cogging torque is established, and the analytical expressions of the cogging torque and the magnetic pole offset angle are derived. The results of the simulation and experiments show that the asymmetric hybrid‐magnet offset motor has lower no‐load back‐EMF harmonic content and rare‐earth material ratio than the traditional permanent magnet motor, and its performance in terms of the cogging torque and the torque ripple is better than that of the traditional permanent magnet motor. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.

Regenerative Braking of BLDC Motor applied to Electric Vehicles

Vehicle uses mechanical brakes to increase friction of wheels for deceleration purposes. However, kinetic energy is converted into thermal energy which reduces the wastage of energy. To avoid this condition regenerative braking scheme has been employed in electric vehicles. This paper proposes a simple method of braking with energy regeneration using BLDC motor for electric vehicles (EVs). Regenerative braking is a procedure in which energy is recovered while brakes are applied. Hence slowing the car, kinetic energy of the car is converted into electrical energy which in turn is used to top up the battery. Due to these, electric vehicles can run for a longer time and extended range without the need of being plugged into an external charger. Usage of brushless DC motor (BLDC) is recommended for implementing the regenerative braking scheme where it can improve efficiency and can extend the driving distance of electric vehicles.

Loss model based controller of fuzzy DTC driven induction motor for electric vehicles using optimal stator flux

Adoption of electric vehicles (EVs) is playing a major role in achieving green energy; however, this suffers from energy density range anxiety. Induction motors (IM) are designed to operate most efficiently under rated conditions. However, for EV applications, it operates at partial load at a constant speed, which reduces its efficiency when operated with nominal flux. In the long run, a lot of battery energy is consumed, which increases the running cost of the vehicle. This paper presents an energy efficient motor drive for EV applications with the objective of reducing battery energy consumption by an optimal reference flux. The optimal value of the stator flux reduces the difference between constant and variable losses, which improves the efficiency and driving range of the vehicle. The optimal flux selection strategies used in the current literature are mostly based on a search control approach, which has convergence issues, is highly complex, and is difficult to implement. In this paper, the Teamwork optimization algorithm (TOA) is used for optimal flux selection under a dynamic driving scenario. The method is examined with realistic EV data under various operating conditions and validated using standard drive cycles. The analysis of efficiency, energy savings, and power input confirms the superiority of the proposed method over other existing methods.

Improvement and application of electromagnetic vibration and noise suppression method for electric vehicle motor

Motor induced Electromagnetic Vibration and Noise (EVN) are mainly affected by Radial Electromagnetic Force Wave (REFW) and related harmonic amplitude. Therefore, in the past discussion on the suppression of motor induced EVN, it usually starts from this aspect. For this reason, this study proposes a method to suppress EVN. Firstly, the influence of the quantity of rotor slots on the function of Induction Motor (IM) is analyzed; Then, the optimization strategy of rotor slot fit is proposed according to the results; Finally, an optimization strategy for the skewness of IM is proposed. Based on the above contents, the experiment realized the suppression of EVN induced by electric vehicle motor. The experimental results show that the parameters of the motor are optimal when the quantity of rotor slots is 53. It is better to weaken the harmonic amplitude related to the low-order REFW. The peak values of the motor using the research strategy at the second and third vibration modes are - 35 db Hz and - 38 db Hz respectively, which are lower than those of the traditional motor. To sum up, the strategies proposed in the study can remarkably suppress the EVN of IM and improve the function of electric vehicles, which will promote the electric vehicle industry ‘s development.

Machine learning predictive model for motor moise by expanding dataset using electromagnetic force characteristics

To understand the variations of electric vehicle motor noise, the electromagnetic force change due to the tilting and the eccentricity between the rotor and the stator on the noise should be studied. However, it takes enormous computation time to consider all the various conditions, so machine learning (ML) model that can reduce the analysis time of electromagnetic force and noise was developed. The developed ML model showed very high accuracy prediction performance with an R2 value higher than 0.99 even for data that was not used at all for training. The speed increase was more than 100 times of FE analysis. The authors doubt that the high accuracy of the developed model implies the potential for electromagnetic force data structure to be much simpler than it appears. Therefore, various analyzes were conducted on the force and uneven magnetic pull. The change in the temporal-spatial main frequency component was not large, and only the change in the side order was meaningful. It was confirmed that to create a predictive model using a smaller dataset for not only the UMP but also all the individual teeth force is possible. This new way of creating a training dataset for an ML model helps to increase the training efficiency. Based on the generated prediction model, it can be used to identify changes in noise characteristics in major rotational orders and derive suitable improvements.

Vibration characteristics of an active mounting system for motion control of a plate-like structure in future mobilities

The vibration and noise caused by electric motors in hybrid and electric vehicles (EVs) generate complex signals with a mid-frequency band, which causes uncomfortable vibration and noise. In order to isolate the vibration and noise, active engine mounting systems based on smart structures have attracted attention. Thus, in this study, the vibration attenuation performance was validated through simulation and feasibility experiments by applying an active mounting system using a piezoelectric stack actuator. A plate structure with three paths, consisting of two passive paths and one active path, was modeled using the lumped parameter method. The source part was excited by a sinusoidal and modulated signal with a mid-frequency band to validate the vibration attenuation performance. Furthermore, (1) mathematical modeling with a source-path-receiver structure was proposed based on lumped parameter modeling, (2) normalized least mean square (NLMS) and multi-NLMS algorithms were applied to implement motion control, and (3) a principal experimental setup was designed to validate the simulation results. Through this process, the vibration attenuation performance of the proposed active mount structure was validated.

Neural Network-Driven Sensorless Speed Control of EV Drive Using PMSM

To reduce pollution and energy consumption, particularly in the automotive industry, energy saving is the main concern, and hence, Electric vehicles (EVs) are getting significantly more attention than vehicles with internal combustion engines (IC engines). Electric motors used in Electric Vehicles (EVs) must have high efficiency for maximum utilization of the energy from the batteries or fuel cells. Also, these motors must be compact, lightweight, less expensive and very easily recycled. Further, to obtain better dynamic performance, various motor control strategies are used to control the speed of the motor. And to have increased reliability, sensorless speed control techniques that offer sufficiently high performance are used. The sensorless speed control techniques are largely divided into three groups: state observer methods, indirect measurement methods and saliency-based methods. Generally, the state observer uses back emf or flux linkage to estimate the speed of the motor. Since the back emf is directly proportional to the rotor speed, at low-speed back emf based method will give poor performance. The current-based Model Reference Adaptive System (MRAS) model is also popular for estimating low speed; however, assessments deteriorate during high performance applications such as EV. This paper presents an artificial neural network (ANN)-deployed sensorless speed control of permanent magnet synchronous motor (PMSM) drive used in EVs. In this paper, the estimation of speed using the current-based MRAS model is discussed and compared with the proposed ANN-based controller, which shows significant improvement in the performance of EV motor drives. The MATLAB simulation and experimental results are presented to validate the proposed algorithm.

Novel revolving heat pipe cooling structure of permanent magnet synchronous motor for electric vehicle

The high temperature rises and uneven axial temperature distribution of permanent magnet synchronous motors applied in electric vehicles can lead to demagnetization of permanent magnets and turn-to-turn short circuit failures in the windings. Thus, a cooling structure based on revolving and fixed annular heat pipes is proposed. That is the revolving heat pipes are installed in the rotor, which are further increasing the rotor's heat transfer efficiency under the centrifugal force of rotor rotation. The fixed annular heat pipes are installed in the stator to cool the windings, especially the end of the windings. The experiments are designed to derive the equivalent thermal conductivity of the proposed revolving and fixed annular heat pipes on this basis. The effectiveness of the proposed cooling structure is verified by computational fluid dynamics simulations which are conducted in three typical operating conditions of the motor used in electric vehicles. The results show that the temperature rise of the rotor, permanent magnet and winding are decreased by up to 70.39%, 69.4%, and 46.18% respectively by the proposed cooling structure. It indicated that the axial temperature rises distribution of heat generating parts can be effectively equalized, and the operating time under maximum torque condition can be effectively extended, that from 30 s to 100 s.

Theoretical and experimental analysis of electric vehicle motor dynamics under the coupling of harmonic current and temperature excitation

The NVH performance of electric vehicles is crucial for human comfort, and the electric drive system is key to NVH performance. Permanent magnet synchronous motors experience high-temperature increases under high-speed operating conditions, resulting in motor structure deformation at high-temperatures. The radial deformation of the stator alters the airgap dimensions of the motor’s electromagnetic field. The airgap of the motor’s magnetic field has high-sensitivity to these changes aggravating the vibration and noise problems. Harmonic currents in high-speed vehicle motors add to these problems. Therefore, motor dynamics must be studied under the joint influences of airgap distortion and harmonic currents. We proposed a method of modeling permanent magnet synchronous motors under the joint effect of harmonic currents and temperature fields. And established an accurate multi-field coupled vibration response prediction model for permanent magnet synchronous motors. The accuracy of the vibration prediction model was subjected to a bench test. The vibration characteristics of the motor were studied using order and spectrum analyses. We found that the airgap magnetic-field distortion, due to the motor and stator thermal deformation, significantly affected the motor vibration characteristics. The main motor vibration noise was caused by the 24th and 48th order electromagnetic force waves. This provides a reference for establishing an accurate vibration prediction model for permanent magnet synchronous motors.

Electromagnetic and Thermal Analysis of a 6/4 Induction Switched Reluctance Machine for Electric Vehicle Application

In this paper, an oil-cooling induction switched reluctance machine (ISRM) is offered. The stator and rotor of the electric machine are non-segmental. However, by placing coils on the rotor, a short magnetic flux path is achieved in the rotor and stator cores. As a result, a higher torque with lower losses is generated. This configuration can be used in high-power electric motors for electric and hybrid vehicles. ISRM is a novel machine and there is a lack of access to its operation and data characteristics. ISRM can be designed in different configurations with various stator and rotor pole numbers and winding strategies. In this study, an oil-cooling three-phase ISRM with 6 stator poles and 4 rotor poles was considered. Firstly, a 2D finite element model of it is created, and its magnetic properties extracted, the flux path, torque and efficiency of the ISRM are calculated, and the results are presented. Secondly, the thermal performance of the motor is analyzed using ANSYS Motor-Cad software. Finally, a prototype of the ISRM and its appropriate drive with the oil cooling system is built and tested. The experimental results and conclusions which prove the ability of the presented machine are presented in the last parts of the paper.

Electric Motor and Transmission Integration for Light-Duty Electric Vehicles: A 2023 Benchmarking Perspective and Component Sizing for a Fleet Approach

Electric Motor and Transmission Integration for Light-Duty Electric Vehicles: A 2023 Benchmarking Perspective and Component Sizing for a Fleet Approach

Performance Validation of PM Assisted SynRM and PMSM with Optimized Design for EV Application

This paper presents the comparison of Permanent Magnet-Assisted Synchronous Reluctance Motor (PMASynRM) and Permanent Magnet Synchronous Motor (PMSM) for the same design parameters and the evaluation of various performance parameters based on the Finite Element (FE) Method. FE Analysis is conducted after selecting the optimized design for PMASynRM and PMSM using an FE tool, with loading conditions to determine various performance parameters. This is achieved by maintaining the same motor dimensions and stator parameters while altering the rotor geometry for both motors. The final simulation results are discussed, and other performance parameters are recorded for comparison purposes. A PMASynRM is introduced, in which the problems of Synchronous Reluctance Motor (SynRM) can be eliminated with a permanent magnet in the rotor flux barrier. Due to higher flux barriers in PMASynRM, the reluctance torque is higher than in PMSM. If the magnet is placed very near to the air gap in PMSM, higher magnet torque is achieved, but due to the high reluctance torque in PMASynRM, the electromagnetic torque of PMASynRM is higher compared to PMSM. The research proves that the proposed design of PMASynRM is the best choice for Electric Vehicle (EV) applications. For PMASynRM, the shape of the flux barrier is not possible to change due to the design limitation of the FE software tool. Further analysis can be conducted by changing the shapes of the flux barriers to propose the most effective barriers. Basic theory and FE analysis of conventional PMSM and SynRM are reported in the literature. An optimal design is proposed through comparative analysis for EV applications to find out the best candidate for an EV motor.

Calculation and Analysis of Motor Thermal Stress With or Without Eccentricity for In-Wheel Electric Vehicle Applications

The requirement of high-power density and the problems of high temperature and uneven air gap caused by environmental constraints make the alternating effect of internal temperature and related constraints between components during the operation of the motor for in-wheel electric vehicle. These effects and constraints will lead to thermal stress and concomitant deformation, and seriously affect the safe operation of in-wheel motors (IWMs) and vehicles. Aiming at the above problems, this paper takes a 15kW IWM as the research object. Based on the analysis of the mutual coupling relationship between the multi-physics field, such as the electromagnetic field, the temperature field, the flow field and the structural field, a thermal stress analysis model of the IWM is established and verified firstly. Then, quantitative calculation of the thermal stress/strain state of the IWM with or without eccentricity is carried out under different working conditions. The analytical results show that the thermal load generated internally leads to the generation of uneven thermal stress and accompanying thermal deformation, and the maximum thermal stress (MTS) and maximum thermal deformation (MTD) do not appear on the same component. Although eccentricity does not affect the position of the MTS and the MTD, it has an important effect on the maximum value of the stress and deformation, especially the eccentricity exceeds 30%. The results also demonstrate that the permanent magnet (PM) is most significantly affected by the eccentricity.