Sensorless Control on a Dual-Fed Flux Modulated Electric Motor

This paper proposes the operation principle and a new flux estimation method for sensorless control strategy for the dual-fed flux modulated electric motor(DFFM).The DFFM is designed based on the flux modulation theory,it includes two stator windings and one rotor which simplify the mechanical structure.The rotor has only modulation iron and no permanent magnets on it,so there is no cogging torque problem in this motor.With adjustment of the outer and inner stator flux rotating frequency and amplitude,different rotation speed and torque of the sandwiched rotor can be gained for the DFFM.Furthermore,an improved flux estimation based sensorless control strategy is performed on the proposed machine to fit the two winding set control situation.The startup and performance of the proposed control strategy is verified by the simulation and experiments.

Design and Construction of a Solar Hybrid Car （Electric Motor and Human Propulsion）

This work presents the design and the construction of a solar hybrid vehicle whose principal driving force is a photovoltaic system, assisted by human propulsion. The solar race of Atacama Desert （Chile） was the In＇st challenge that the solar vehicle faced, with a maximum catchment area of 4 m^2 storage 1,500 Wh and a maximum cost of 7,000 USD. Built vehicle was tested, reaching speeds on fiat terrain of 40 km/h with engine and 50 km/h with human-powered contribution. Proposed design could be projected as a vehicle for transporting person average Latin American roads.

Review and Development of Electric Motor Systems and Electric Powertrains for New Energy Vehicles

This paper presents a review on the recent research and technical progress of electric motor systems and electric powertrains for new energy vehicles.Through the analysis and comparison of direct current motor,induction motor,and synchronous motor,it is found that permanent magnet synchronous motor has better overall performance;by comparison with converters with Si-based IGBTs,it is found converters with SiC MOSFETs show significantly higher efficiency and increase driving mileage per charge.In addition,the pros and cons of different control strategies and algorithms are demonstrated.Next,by comparing series,parallel,and power split hybrid powertrains,the series-parallel compound hybrid powertrains are found to provide better fuel economy.Different electric powertrains,hybrid powertrains,and range-extended electric systems are also detailed,and their advantages and disadvantages are described.Finally,the technology roadmap over the next 15 years is proposed regarding traction motor,power electronic converter and electric powertrain as well as the key materials and components at each time frame.

Decentralized Dynamic Event-Triggered Communication and Active Suspension Control of In-Wheel Motor Driven Electric Vehicles with Dynamic Damping

This paper addresses the co-design problem of decentralized dynamic event-triggered communication and active suspension control for an in-wheel motor driven electric vehicle equipped with a dynamic damper. The main objective is to simultaneously improve the desired suspension performance caused by various road disturbances and alleviate the network resource utilization for the concerned in-vehicle networked suspension system. First, a T-S fuzzy active suspension model of an electric vehicle under dynamic damping is established. Second,a novel decentralized dynamic event-triggered communication mechanism is developed to regulate each sensor's data transmissions such that sampled data packets on each sensor are scheduled in an independent manner. In contrast to the traditional static triggering mechanisms, a key feature of the proposed mechanism is that the threshold parameter in the event trigger is adjusted adaptively over time to reduce the network resources occupancy. Third, co-design criteria for the desired event-triggered fuzzy controller and dynamic triggering mechanisms are derived. Finally, comprehensive comparative simulation studies of a 3-degrees-of-freedom quarter suspension model are provided under both bump road disturbance and ISO-2631 classified random road disturbance to validate the effectiveness of the proposed co-design approach. It is shown that ride comfort can be greatly improved in either road disturbance case and the suspension deflection, dynamic tyre load and actuator control input are all kept below the prescribed maximum allowable limits, while simultaneously maintaining desirable communication efficiency.

STUDY ON POWER SPARE COEFFICIENT OF ELECTRICAL MOTOR IN LARGE PUMP STATION BASED ON RELIABILITY

Characters of head of low head pump station and the pump shaft power areanalyzed. Influence of each single factor on pump shaft power is expressed as change of specificshaft power. (non-dimensional) and the probability density function is determined. Influences ofmultiple factors on pump shaft power are analyzed. Method of calculating none over-loadedprobability of motor by integration by successive reductions is put forward and then relationbetween power spare coefficient and none over-loaded reliability of electric motor is established.Influences of all factors on pump shaft power being considered completely; power spare coefficientsof motor are calculated in three kinds of heads (changing and unchanging), two kinds of dirty-outconditions. Electrical motor power spare coefficients should be chosen as 1.20 approx 1.44, 1.11approx 1.19, 1.09 approx.14 respectively when pump heads are 4, 7, 9.5 m. The results mean much toreasonable choose of electrical motors in large pump stations, increasing reliability of pump unitsand saving equipment investment.

Torque Distribution of Electric Vehicle with Four In-Wheel Motors Based on Road Adhesion Margin

With the worsening of energy crisis and environmental pollution,electric vehicles with four in?wheel motors have been paid more and more attention. The main research subject is how to reasonably distribute the driving torque of each wheel. Considering the longitudinal motion,lateral motion,yaw movement and rotation of the four wheels,the tire model and the seven DOF dynamic model of the vehicle are established in this paper. Then,the torque distribution method is proposed based on road adhesion margin,which can be divided into anti ? slip control layer and torque distribution layer. The anti?slip control layer is built based on sliding mode variable structure control,whose main function is to avoid the excessive slip of wheels caused by road conditions. The torque distribution layer is responsible for selecting the torque distribution method based on road adhesion margin. The simulation results show that the proposed torque distribution method can ensure the vehicle quickly adapt to current road adhesion conditions,and improve the handling stability and dynamic performance of the vehicle in the driving process.

Multi-objective Optimization of Differential Steering System of Electric Vehicle with Motorized Wheels

A differential steering system is presented for electric vehicle with motorized wheels and a dynamic model of three-freedom car is built.Based on these models,the quantitative expressions of the road feel,sensitivity,and operation stability of the steering are derived.Then,according to the features of multi-constrained optimization of multi-objective function,a multi-island genetic algorithm(MIGA)is designed.Taking the road feel and the sensitivity of the steering as optimization objectives and the operation stability of the steering as a constraint,the system parameters are optimized.The simulation results show that the system optimized with MIGA can improve the steering road feel,and guarantee the operation stability and steering sensibility.

Efficiency of Model Induction Motor Using Various Non-Oriented Electrical Steels

The performance of a 3-phase 6-pole 400 W inverter-drive induction motor was investigated using a variety of non-oriented electrical steels for stator core at PWM inverter fundamental wave frequencies of 30 to 300 Hz. There existed an optimum Si content of the material depending on the tooth flux density. Both reduction of material thickness and stress-relief annealing of the stator core improved the motor efficiency. The influence of Si content on the efficiency was small at lower PWM frequencies, while at higher frequencies the motor efficiency increased with increasing Si content. The Cu loss WC increased and the Fe loss Wi counteractiveiy decreasedwith increasing Si content at lower frequencies; while at higher frequencies Wi had dominant effect on the efficiency. Newly developed materials RMA, having lower Fe losses after stress-relief annealing and higher flux densities with lower Si contents, showed motor efficiencies superior to conventional J1S grade materials with comparable Fe losses.

Early application of percutaneous neuromuscular electric stimulation in interfering motor function of limbs and difference in temperature of axilla of patients with ischemic stroke

BACKGROUND： Temperature of axilla could be affected due to motor dysfunction of limbs and neural changes of vessel after ischemic stroke. OBJECTIVE： To observe the effect of percutaneous neuromuscular electric stimulation （PNES） on difference in temperature of axilla and analyze the relationship between function of limbs and difference in temperature of axilla. DESIGN： Randomized grouping and controlled observation SETTING： Department of Neurology, General Hospital of Shenyang Military Area Command of Chinese PLA PARTICIPANTS： Sixty patients with ischemic stroke were selected from Neurological Department of General Hospital of Shenyang Military Area Command of Chinese PLA from January to June 2003. All cases were diagnosed with clinical diagnosis criteria of ischemic stroke established by the Fourth Chinese Classification of Cerebrovasular Disease and CT examination and received neuromuscular electric stimulation （NES）. Patients were randomly divided into control group and treatment group with 30 in each group. METHODS： Control group： Patients received routinely neurological therapy. Treatment group： Except routine therapy, patients suffered from NES at 48 hours after hospitalization. NMT-91 NES equipment was used to stimulated injured limbs with low frequency once 30 minutes a day in total of 10 times a course, especially extensor muscle of upper limb and flexor muscle of lower limb. Prescription of hemiplegia was internally decided by equipment with the output frequency of 200 Hz. Intensity of electric output could cause muscle contraction. The therapy needed two or three courses. Temperature of bilateral axilla was measured every day to calculate the difference with the formula of （temperature of axilla on the injured side - temperature of axilla on the healthy side）. Motor function of limbs was measured with FugI-Meyer Motor Assessment （FMA） during hospitalization and at 2 and 4 hours after hospitalization. Among 90 points, upper and lower limb function was 54, equilibrium function 10, sensory function 10, and motion of joint 16. The higher the scores were, the better the function was. Correlation of data was dealt with linear correlation analysis. MAIN OUTCOME MEASURES ： Assessment and correlation between difference in temperature of axilla and motor function of injured limbs during hospitalization and at 2 and 4 weeks after hospitalization. RESULTS： All 60 patients with ischemic stroke were involved in the final analysis. ① Difference in temperature： Difference of 2 and 4 weeks after hospitalization was lower than that in control group and at just hospitalization [treatment group： （0.056±0.000）, （0.024±0.003） ℃; control group： （0.250±0.001）, （0.131 ±0.001）℃; hospitalization; （0.513±0.001） ℃, P 〈 0.05-0,01]. ② FMA scores： Scores of 2 and 4 weeks after hospitalization were higher than those in control group and at just hospitalization [treatment group; （43.50±15.09）, （67.97 ±18.21） points; control group： （33.33 ±13.54）, （40.87±19.34） points; hospitalization： （26.43 ±11.87） points, P 〈 0.05-0.01]. ③ Correlation： Difference in temperature of axilla was negative correlation with FMA scores （c=- -0.255 1, P 〈 0.05）. CONCLUSION： ① PNES can accelerate recovery of limb function and decrease temperature of axilla of patients with ischemic stroke. ② The lower the difference in temperature is, the better the functional recovery is.

The use of permanent magnet motor for Tesla electric vehicle stimulates the demand for rare earth Nd

On March 13th,Reuters reported that the long run version of Tesla Model 3 will use permanent magnet motors.One of the materials for this type of motor is rare earth metal neodymium,which will further increase the supply pressure of neodymium.Governments around the world are committed to reducing the harmful emissions produced by fossil fuel cars,pushing up demand for electric vehicles

中国电动机质量监管及标准体系概述

This paper systematically analyzes the product quality supervision methods in China,introduces the main functions of market regulation departments and the product supervision and random inspection process,and introduces the channels for feedback on consumers’quality and safety problems,the online platform for consumer problem disposal.It also summarizes the main standards categories and standards systems for electric motors in China,and the standards and key inspection items for supervision and random inspection.

A Fuzzy-based Sliding Mode Control Approach for Acceleration Slip Regulation of Battery Electric Vehicle

Due to quick response and large quantity of electric motor torque,the traction wheels of battery electric vehicle are easy to slip during the initial phase of starting.In this paper,a sliding mode control approach of acceleration slip regulation is designed to prevent the slip of the traction wheels.The wheel slip ratio is used as the state variable for the formulation of system dynamics model.The fuzzy algorithm is utilized to adjust the switch function of sliding mode controller.After stability and robustness analysis,the sliding mode control law is transferred into C code and downloaded into vehicle control unit,which is validated under wet and dry road conditions.The experimental results with a small overshoot and a quick response during starting indicate that the sliding mode controller has good control efect on the slip ratio regulation.This article proposes an acceleration slip regulation method that improves the safety during acceleration for battery electric vehicle.

Research on Hybrid Input Mechanical Press Driven by Two Motors

Given the speed requirements of a mechanical press slider, a differential gear train is adopted instead of the belt and gear drive of a general mechanical press. Two electric motors are used to drive the differential gear train with hybrid input. Based on the working principle of a differential gear train, the angular speed equations and the power dis- tribution equations of the input-output system are established. By controlling the angular speeds of the two motors, the slider can move at different speeds. Taken a JH23-100 type mechanical press as example, the driving system is designed and the power of two motors determined. The simulated results show that the highest slider speed in the mechanical press approaches 39 mm/s only at the forging-punching stage, far less than the 232 mm/s of a general JH23-100 type mechanical press. This provides a new scheme to realize low-speed forging-punching technology from a mechanical press.

DESIGN AND EXPERIMENT OF ELECTRIC BUS

Performance and reliability experiments on BJD-6100EV electric buses, jointlydeveloped by Beijing Institute of Technology and Beijing Public Transport Company, are introduced.Output power model of battery pack is established and maximum output power is analyzed. A permanentmagnetic direct current (PMDC) motor with enhanced windings is developed for the bus. Torque-speedcharacteristics of the motor are modeled and performance of electric bus is analyzed. Computationalmethod of the range of electric bus is proposed and discussed. Experiments show that electric buscan realize design requirements. Computational methods are verified with the help of field test. Itis expected that design and computation method will provide helpful reference to development ofelectric vehicles.

A General Method to Compute the Electric Flux Lines between Two Magnet Wires in Close Contact and Its Application for the Evaluation of Partial Discharge Risks in the Slots of Electric Machines Embedded in Future Transportation Systems

The sizing of the Electrical Insulation System (EIS) is an important challenge in electric motors of higher specific power driven by faster inverters. That keeps increasing the electric stress which the winding is submitted in the stator slot. Consequently, Partial Discharges (PD) are more likely to occur. Nowadays, the Paschen’s criterion is widely used to evaluate the risk of partial discharge. It requires the knowledge of electric field lines. This paper presents a method to precisely compute the electric field lines in a two-dimensional (2D) electrostatic problem. The field of study is composed of two magnet wires in close contact. Such configuration is representative of the turn-to-turn interaction in an electric motor slot. The problem is solved using the scalar potential formulation only. The notion of flux tubes is used for the post process of the electric field lines in a developed numerical code on Matlab. The developed method is compared to a ballistic method already included on Matlab. The work presented here is included in an automatic tool to suppress or reduce the partial discharge risk in a stator slot of high power density motor destined for future transportation systems.

Technical Approaches Towards Ultra-High Power Density SiC Inverter in Electric Vehicle Applications

Along with the rapid growth in electric vehicle(EV)market,higher power density and more efficient motor drive inverters are required.It is well known that silicon carbide(SiC)has advantages of high temperature,high efficiency and high switching frequency.It is believed that the appropriate utilization of these merits can pave the way to ultra-high power density inverters.This paper presents issues about SiC chip’s current-carrying capability enhancement which is crucial for a compact inverter of tens and hundreds of kilowatts.Technical approaches towards ultra-high power density EV inverter including SiC module packaging,dc-link capacitor function analysis and system level integration are discussed.Different PWM algorithms which may improve efficiency and help to reduce the inverter volume are also studied.

The influence of various grease compositions and silver nanoparticle additives on electrically induced rolling-element bearing damage

Leakage currents accelerate surface degradation of metal contacts via small scale arcing across lubricating films,but recent observations suggest that metallic nanoparticle additives in lubricants may be useful to improve contact performance.These findings prompted a study that examined electrically induced surface pitting of steel contacts in the presence of several lubricating greases including some containing nanometer-sized colloidal silver(Ag)particles.Reciprocating rolling sphere-on-disk experiments were conducted under electro-tribological loads employing polyurea greases derived from mineral and synthetic base oils with and without additives.Friction forces and electrical resistance were monitored continuously during the tests;surface changes were characterized by means of optical spectroscopy,stylus profilometry,and scanning electron microscopy(SEM)including compositional analysis using energy dispersive spectroscopy(EDS).The observations demonstrate that surface pitting induced by arcing occurs mainly at the points were the rolling motion changes direction and that eroded metal is deposited along the wear grove.Micron-sized pits are formed which contain carbon and oxygen indicating that arcing causes decomposition of the hydrocarbon lubricants.Numerous findings indicate a significant inhibition of pitting is induced by the Ag nanoparticles;some greases containing other additives exhibit a similar,although less pronounced,effect.

Design of Electrical/Mechanical Hybrid 4-Redundancy Brushless DC Torque Motor

This article presents a novel electrical/mechanical hybrid 4-redundancy brushless DC torque motor （BLDCM）, which has found applications in direct drive actuators （DDA） of aerial vehicles. This motor is characteristic of electrical/mechanical hybrid 4-redundancy by securing two stators along with two rotors on the same shaft. Each stator contains two sets of windings embed- ded in separated slots. Furthermore, compared to the scheme of two electrical dual-redundancy BLDCMs linked by a mechanical transmission, the proposed motor has lower volume and lighter weight, eliminates the nonlinearity caused by the gap of the me- chanical transmission, moderates the requirement for the torque balance between redundancies and reduces the cogging torque by shifting the magnets. Both magnetic circuit calculation and the finite element analysis （FEA） of the electromagnetic field are conducted to optimize the design process. A prototype motor has been produced and tested. The results indicate that its perform- ances comply with the requirements presented by designers. Moreover, the position frequency response of the prototype in the DDA＇s unloaded situation has also demonstrated the fulfillment of desired dynamic characteristics.

Modeling and Testing of the Multi-pole Field of a Motor for Pure Electric Vehicles

From the principles of electromechanical energy conversion and electromagnetic torque generation, our study evaluatedthe mathematical model of the electromagnetic torque and the vector control method of motors. An analysis of motor typesindicates that the electromechanical energy conversion component is interchangeable. Three distinct types of motor structures,namely DC, induction, and synchronous, are possible, all three being commonly used in pure electric vehicles. For each motortype, simulation models were developed using Modelica, a modeling language for object-oriented multi-domain physicalsystem. A test model of each motor type was configured in the MWorks simulation platform. With a representative motor,specifically the permanent-magnet DC motor, the asynchronous induction motor, and the permanent-magnet synchronousmotor, mechanical properties were simulated and analyzed. The simulation results show that the characteristics of each motormodel are consistent with the theoretical and engineering performance of the representative motor. Therefore, modeling,motor control, and performance testing of a unified multi-pole-field motor, which is used in pure electric vehicles, have beenachieved.

Primary studies on integration optimization of differential steering of electric vehicle with motorized wheels based on quality engineering

The model of the differential steering system(DSS) of electric vehicle with motorized wheels and the three-degree-of-freedom dynamic model of vehicle are built.Based on these models,the concepts and quantitative expressions of steering road feel,steering portability and steering stability are proposed.Through integrating the Monte Carlo descriptive sampling,elitist non-dominated sorting genetic algorithm(NSGA-II) and Taguchi robust design method,the system parameters are optimized with steering road feel and steering portability as optimization targets,and steering stability and steering portability as constraints.The simulation results show that the system optimized based on quality engineering can improve the steering road feel,guarantee steering stability and steering portability and thus provide a theoretical basis for the design and optimization of the electric vehicle with motorized wheels system.