Synthesis of Fractional-order PI Controllers and Fractional-order Filters for Industrial Electrical Drives

This paper introduces an electrical drives control architecture combining a fractional-order controller and a setpoint pre-filter. The former is based on a fractional-order proportional-integral(PI) unit, with a non-integer order integral action, while the latter can be of integer or non-integer type. To satisfy robustness and dynamic performance specifications, the feedback controller is designed by a loop-shaping technique in the frequency domain. In particular, optimality of the feedback system is pursued to achieve input-output tracking. The setpoint pre-filter is designed by a dynamic inversion technique minimizing the difference between the ideal synthesized command signal(i.e., a smooth monotonic response) and the prefilter step response. Experimental tests validate the methodology and compare the performance of the proposed architecture with well-established control schemes that employ the classical PIbased symmetrical optimum method with a smoothing pre-filter.

Robust Multiobjective and Multidisciplinary Design Optimization of Electrical Drive Systems

Design and optimization of electrical drive systems often involve simultaneous consideration of multiple objectives that usually contradict to each other and multiple disciplines that normally coupled to each other.This paper aims to present efficient system-level multiobjective optimization methods for the multidisciplinary design optimization of electrical drive systems.From the perspective of quality control,deterministic and robust approaches will be investigated for the development of the optimization models for the proposed methods.Meanwhile,two approximation methods,Kriging model and Taylor expansion are employed to decrease the computation/simulation cost.To illustrate the advantages of the proposed methods,a drive system with a permanent magnet synchronous motor driven by a field oriented control system is investigated.Deterministic and robust Pareto optimal solutions are presented and compared in terms of several steady-state and dynamic performances(like average torque and speed overshoot)of the drive system.The robust multiobjective optimization method can produce optimal Pareto solutions with high manufacturing quality for the drive system.

Two-vector Dimensionless Model Predictive Control of PMSM Drives Based on Fuzzy Decision Making

Model predictive controls(MPCs) with the merits of non-linear multi-variable control can achieve better performance than other commonly used control methods for permanent magnet synchronous motor(PMSM) drives.However,the conventional MPCs have various issues,including unsatisfactory steady-state performance,variable switching frequency,and difficult selection of appropriate weighting factors.This paper proposes two different improved MPC methods to deal with these issues.One method is the two-vector dimensionless model predictive torque control(MPTC).Two cost functions(torque and flux) and fuzzy decision-making are used to eliminate the weighting factor and select the first optimum vector.The torque cost function selects a second vector whose duty cycle is determined based on the torque error.The other method is the two-vector dimensionless model predictive current control(MPCC).The first vector is selected the same as in the conventional MPC method.Two separate current cost functions and fuzzy decision-making are used to select the second vector whose duty cycle is determined based on the current error.Both proposed methods utilize the space vector PWM modulator to regulate the switching frequency.Numerical simulation results show that the proposed methods have better steady-state and transient performances than the conventional MPCs and other existing improved MPCs.

Inertia Matching During Dynamic Simulation of Vehicle Drive System on Test Bench

Framework and basic parameters of a test bench for motor drive system of electric vehicle (EV) are illuminated. Two kinds of electric drive models, one was for the electric vehicle drived on real road, the other was for that on test bench, are put forward. Then, dynamic analysis of these models is made in detail. Inertia matching method of the test bench is researched and some useful formulas and graphs are brought forward. The experiment of an electric bus is introduced in order to explain the usage of this inertia matching method.

Four Wheel Independent Drive Electric Vehicle Lateral Stability Control Strategy

In this paper,a kind of lateral stability control strategy is put forward about the four wheel independent drive electric vehicle.The design of control system adopts hierarchical structure.Unlike the previous control strategy,this paper introduces a method which is the combination of sliding mode control and optimal allocation algorithm.According to the driver’s operation commands(steering angle and speed),the steady state responses of the sideslip angle and yaw rate are obtained.Based on this,the reference model is built.Upper controller adopts the sliding mode control principle to obtain the desired yawing moment demand.Lower controller is designed to satisfy the desired yawing moment demand by optimal allocation of the tire longitudinal forces.Firstly,the optimization goal is built to minimize the actuator cost.Secondly,the weighted least-square method is used to design the tire longitudinal forces optimization distribution strategy under the constraint conditions of actuator and the friction oval.Beyond that,when the optimal allocation algorithm is not applied,a method of axial load ratio distribution is adopted.Finally,Car Sim associated with Simulink simulation experiments are designed under the conditions of different velocities and different pavements.The simulation results show that the control strategy designed in this paper has a good following effect comparing with the reference model and the sideslip angle is controlled within a small rang at the same time.Beyond that,based on the optimal distribution mode,the electromagnetic torque phase of each wheel can follow the trend of the vertical force of the tire,which shows the effectiveness of the optimal distribution algorithm.

Direct Yaw Moment Control for Distributed Drive Electric Vehicle Handling Performance Improvement

For a distributed drive electric vehicle（DDEV） driven by four in-wheel motors, advanced vehicle dynamic control methods can be realized easily because motors can be controlled independently, quickly and precisely. And direct yaw-moment control（DYC） has been widely studied and applied to vehicle stability control. Good vehicle handling performance： quick yaw rate transient response, small overshoot, high steady yaw rate gain, etc, is required by drivers under normal conditions, which is less concerned, however. Based on the hierarchical control methodology, a novel control system using direct yaw moment control for improving handling performance of a distributed drive electric vehicle especially under normal driving conditions has been proposed. The upper-loop control system consists of two parts： a state feedback controller, which aims to realize the ideal transient response of yaw rate, with a vehicle sideslip angle observer; and a steering wheel angle feedforward controller designed to achieve a desired yaw rate steady gain. Under the restriction of the effect of poles and zeros in the closed-loop transfer function on the system response and the capacity of in-wheel motors, the integrated time and absolute error（ITAE） function is utilized as the cost function in the optimal control to calculate the ideal eigen frequency and damper coefficient of the system and obtain optimal feedback matrix and feedforward matrix. Simulations and experiments with a DDEV under multiple maneuvers are carried out and show the effectiveness of the proposed method： yaw rate rising time is reduced, steady yaw rate gain is increased, vehicle steering characteristic is close to neutral steer and drivers burdens are also reduced. The control system improves vehicle handling performance under normal conditions in both transient and steady response. State feedback control instead of model following control is introduced in the control system so that the sense of control intervention to drivers is relieved.

Slip-Control Strategy of Dual Independent Electric Drive Tracked Vehicle

In order to improve the brake performance of a dual independent electric drive tracked vehicle,a dynamic model for braking situation was established.Then,a sliding model controller(SMC)with an auxiliary system was designed to control the slip and its effectiveness was proved.A hardware-in-loop simulation through MATLAB/XPC was compared with the normal SMC and normal integral sliding mode controller(ISMC),the results show that SMC with the auxiliary system has a better performance:a smaller overshoot and steady state error.The disturbance is suppressed effectively.In the initial speed of 65.km/h,the brake distance was shortened by 3.4%and 6.8%compared with the other two methods,respectively.Finally,initial speeds of 30-36.km/h tests was carried out on a flat soil road.Compared with a no-control brake,the displacement was shortened by 1.8.m.It demonstrates the effectiveness of the slip-control strategy.In the same situation,the error between the simulation and test is 18.1%,which validates the accuracy of models.

Multiple Purpose Simulation for Electric Vehicles

Aim Toshorten integral design period of electric vehicles Methods The electric vehicle simulation program(EVSP), a modular user-friendly program which is written in Borland C++ OWL for Windows was developed. Results EVSP allows simulating the dynamic and the economy performance of electric vehicles.EVSP provides many kinds of data input module,a large components library of electric vehicles and several kinds of speed cycle with these library,it is easily to develop a new concept of different drive trains or even to compare or improve the existing electric vehicles. The paper simulated the performance of YW6120DD Electric Bus, and analyzed the test results comparing with simulation results Conclusion The simulation results indicate that the EVSP may contribute to the developments of electric vehicles in general and the definition of the optimal match management in the drive train in particular.

Method of Electric Powertrain Matching for Battery-powered Electric Cars

The current match method of electric powertrain still makes use of longitudinal dynamics, which can’t realize maximum capacity for on-board energy storage unit and can’t reach lowest equivalent fuel consumption as well. Another match method focuses on improving available space considering reasonable layout of vehicle to enlarge rated energy capacity for on-board energy storage unit, which can keep the longitudinal dynamics performance almost unchanged but can’t reach lowest fuel consumption. Considering the characteristics of driving motor, method of electric powertrain matching utilizing conventional longitudinal dynamics for driving system and cut-and-try method for energy storage system is proposed for passenger cars converted from traditional ones. Through combining the utilization of vehicle space which contributes to the on-board energy amount, vehicle longitudinal performance requirements, vehicle equivalent fuel consumption level, passive safety requirements and maximum driving range requirement together, a comprehensive optimal match method of electric powertrain for battery-powered electric vehicle is raised. In simulation, the vehicle model and match method is built in Matlab/simulink, and the Environmental Protection Agency (EPA) Urban Dynamometer Driving Schedule (UDDS) is chosen as a test condition. The simulation results show that 2.62% of regenerative energy and 2% of energy storage efficiency are increased relative to the traditional method. The research conclusions provide theoretical and practical solutions for electric powertrain matching for modern battery-powered electric vehicles especially for those converted from traditional ones, and further enhance dynamics of electric vehicles.

OPTIMAL TORQUE CONTROL STRATEGY FOR PARALLEL HYBRID ELECTRIC VEHICLE WITH AUTOMATIC MECHANICAL TRANSMISSION

In parallel hybrid electrical vehicle （PHEV） equipped with automatic mechanical transmission （AMT）, the driving smoothness and the clutch abrasion are the primary considerations for powertrain control during gearshift and clutch operation. To improve these performance indexes of PHEV, a coordinated control system is proposed through the analyzing of HEV powertrain dynamic characteristics. Using the method of minimum principle, the input torque of transmission is optimized to improve the driving smoothness of vehicle. Using the methods of fuzzy logic and fuzzy-PID, the engaging speed of clutch and the throttle opening of engine are manipulated to ensure the smoothness of clutch engagement and reduce the abrasion of clutch friction plates. The motor provides the difference between the required input torque of transmission and the torque transmitted through clutch plates. Results of simulation and experiments show that the proposed control strategy performs better than the contrastive control system, the smoothness of driving and the abrasion of clutch can be improved simultaneously.

Design and Research of a Portable Tool for Assisting Elderly People Walking

Based on the serious aging of our country′s population,starting from the impact on the quality of life of the elderly,this paper first analyzes the factors affecting the lives of the elderly,and makes predictions based on my country′s elderly care industry market.After research,a portable tool for assisting elderly people walking is designed,in which electric drive,steering mechanism and seat functions are added by ordinary auxiliary walking tools.Users can sit down and ride when they are tired,mainly including seats and walking functions.The characteristics of its users and various influencing factors are analyzed.The research results can guide the solution of the current portable tools that assist the elderly in walking.

Fusion of ERT Images Based on Dempster-Shafer's Evidence Theory

In this paper, an electrical resistance tomography(ERT) imaging method is used as a classifier, and then the Dempster-Shafer's evidence theory with fuzzy clustering is integrated to improve the ERT image quality. The fuzzy clustering is applied to determining the key mass function, and dealing with the uncertain, incomplete and inconsistent measured imaging data in ERT. The proposed method was applied to images with the same investigated object under eight typical current drive patterns. Experiments were performed on a group of simulations using COMSOL Multiphysics tool and measurements with a piece of porcine lung and a pair of porcine kidneys as test materials. Compared with any single drive pattern, the proposed method can provide images with a spatial resolution of about 10% higher, while the time resolution was almost the same.

Vehicles PEMFC Power System Mathematical Model for Integrated Design

In this paper, the mathematical dynamical model of a PEMFC （proton exchange membrane fuel cells） stack, integrated with an automotive synchronous electrical power drive, developed in Matlab environment, is shown. Lots of simulations have been executed in many load conditions. In this paper, the load conditions regarding an electrical vehicle for disabled people is reported. The innovation in this field concerns the integration, in the PEMFC stack mathematical dynamic model, of a synchronous electrical power drive for automotive purposes. Goal of the simulator design has been to create an useful tool which is able to evaluate the behaviour of the whole system so as to optimize the components choose. As regards the simulations with a synchronous electrical power drive, the complete mathematical model allows to evaluate the PEMFC stack performances and electrochemical efficiency.

A New Topology of a Variable Output-Voltage DC-DC Converter for Fuel Cell Vehicles

The aim of this paper is to present a new topology of a DC-DC power converter for conditioning the current and voltages behaviors of embarked energy sources used in electrical vehicles. The fuel cells in conjunction with ultra-capacitors have been chosen as the power supply. The originality of the proposed converter is to use a variable voltage of the DC bus of the vehicle. The goal is to allow a better energy management of the embedded sources onboard the vehicle by improving its energy efficiency. After presenting and explaining the topology of the converter, some simulation and experiments results are shown to highlight its different operation modes.

A strong robustness open-circuit fault diagnosis strategy for novel fault-tolerant electric drive system based on d-q-axis current signal

To diagnose the Open-Circuit(OC)fault in the novel fault-tolerant electric drive system,based on d-q-axis current signal,a strong robustness diagnosis strategy is proposed and investigated.Fewer independent power supplies and converters are required in the novel fault-tolerant electric drive system based on Dual-Winding Permanent Magnet Motor(DWPMM),and the system’s reliability,usage ratio and power density have been improved compared to the conventional fault-tolerant motor drive system.However,the novel fault-tolerant electric drive system has the OC fault diagnostic false alarms issue when load changes suddenly or under light-load condition.And it lacks the research on the diagnostic method when the system encounters intermittent OC fault in power switches.By theory derivation,simulation and experimental verification,it can be concluded that the proposed strong robustness OC fault diagnosis strategy based on d-q-axis current signal can overcome the OC fault diagnostic false alarms issue when load changes suddenly or under light-load condition.And it can detect and locate the OC fault of single-phase winding in real time,and diagnose the intermittent OC fault of power switches.

Predictive Field-Oriented Control for Electric Drives

Model predictive field-oriented control(PFOC)is a novel control strategy belonging to the class of finite control set model predictive control(FCS-MPC)for electric drive systems.It is a direct control scheme which minimizes the cost function through the convergence of errors between the given and predictive stator currents.In this paper,PFOC is thoroughly presented and analyzed through its dynamics and steady state operations under wide range of speed and varying torque conditions.In light of PFOC’s model based characteristics,its robustness an d influence under model parameters’mismatch is also investigated.Experiments are conducted to show these performance and sensitivities.

Multiphysics Field Co-simulation Research Based on Electric Drive System for a Specific Type of Car

Electric drive systems for new energy cars are complex systems that should have multivariate,strong coupling,and non-linear characteristics and should also involve the multiphysics field.The singular simulation software used at present in the modeling of electric drive systems cannot simulate the influences of all the physics fields on the operating system.The co-simulation model used in this paper was based on a specific type of car.The motor control algorithm model was built in MATLAB/Simulink,the electromagnetic finite element model of the motor was built in ANSYS EM-Maxwell,and the motor controller hardware circuit was built in ANSYS EM-Simplorer.To make real-time connections among these software platforms,a multi-software co-simulation platform was built,and the co-simulation platform’s simulation results were input into STAR CCM+software to enable finite element modeling of the motor and running of thermal analysis.When compared with the electric drive system model built using single Simulink software,the simulation results from this co-simulation platform were more realistic and were shown to be closer to reality when the dynamic characteristics of the electric drive system’s power semiconductor switching devices and the motor’s electromagnetic characteristics were considered.Finally,by benchmarking the multiphysics field co-simulation platform simulation results using dyno bench test results,the validity of the co-simulation platform was verified and the development of the multiphysics field co-simulation of the basic electric drive system was complete.

Planting uniformity performance of motor-driven maize precision seeding systems

Low accuracy planting uniformity affects yield.Seed meter type and forward speed typically interfere with the planting uniformity accuracy of motor-driven seeding systems.Two types of maize precision planters equipped with motor-driven planting systems are investigated in this study to ascertain the rule of planting uniformity in both simulated and field speeds.The simulated speed increases from 5 to 12 km/h at a 1 km/h interval in a laboratory environment.The test results show that the quality of feed index(QTFI)of the two planters decreased by 16.79%and 9.88%.This is primarily attributed to the increase in the miss index(MISS)by 11.62%and 9.70%,respectively.The field speed was set to four levels from 5 to 12 km/h in a field environment.The plant spacing scatter distribution results were analyzed,and the results of the two planters indicated that the average positive difference of the two planters linearly increased with the forward speed,and the negative difference of the two planters did not exhibit a linear correlation.The number of positive moving average points was 2.49 times greater than that of the negative moving average points of the finger pick-up maize precision planter,and 4.49 times in the air-suction maize precision planter.The results indicated that the increase of the positive difference of plant spacing is the major effect factor in the field planting uniformity of the two motor-driven maize precision planters.In addition,the plant spacing corresponded to the distribution frequency of the two planters in field was close to the target seed spacing of 25 cm with a max coefficient of variation(CV)of 21.55%and 20.66%,respectively,and those plant spacing values corresponded to max distribution frequency of the two planters at the four level field speeds were(24.69±0.63)cm and(25.63±0.32)cm,respectively.However,the multiples index(MUL)changed randomly affected by the increasing speed.The research results provide a direction for the optimization design of motor-driven maize precision planters.

Progress in Automotive Transmission Technology

Much progress has been made in the development of automotive transmissions over the past 20 years,e.g.,an increased speed number,expanded ratio spread and improved efficiency and shift quality.Automotive transmissions are moving toward electrification in response to stringent legislation on emissions and the pressing demand for better fuel economy.This paper reviews progress in automotive transmission technology.Assisted by computer-aided programs,new transmission schemes are constantly being developed.We therefore first introduce the synthesis of the transmission scheme and parameter optimization.We then discuss the progress in the transmission technology of a conventional internal combustion engine vehicle in terms of new layouts;improved efficiency;noise,vibration and harshness technology;and the shifting strategy and control technology.As the major development trend,transmission electrification is subsequently discussed;this discussion includes the configuration design,energy management strategy,hybrid mode shifting control,single-speed and multi-speed electric vehicle transmission and distributed electric drive.Finally,a summary and outlook are presented for conventional automotive transmissions,hybrid transmissions and electric vehicle transmissions.

Progress review of US-China joint research on advanced technologies for plug-in electric vehicles

The United States and China are the world's largest automobile markets and oil consumers, and both face a severe challenge to conserve energy and reduce tailpipe emissions. Thus, both countries urgently need to transform conventional internal combustion engines to electrified powertrains. Targeting the advanced core technologies of plug-in electric vehicles(PEVs), a joint research collaboration between China and the US, called the "Clean Vehicle Consortium"(CVC), was set up in 2010. Six years of collaboration on PEV technologies has resulted in significant progress in three technical areas. Based on CVC publications,we review herein the progress made by the CVC research efforts on three key advanced PEV technologies. This includes the development of a safe battery with an energy density of 260 W h kg^(-1) and a systematic method for designing safe traction battery systems. Thus, a breakthrough in high power density and efficient traction motor systems has occurred. In addition to discussing advanced electric-drive powertrains, we also discuss global energy management strategies that aim to improve PEV energy efficiency. This discussion covers scientific and comprehensive analysis methods to analyze energy systems, which include costbenefit analyses of plug-in hybrid electric vehicles, life-cycle assessments for evaluating vehicle emissions, and PEV-ownership projections.