This paper presents a novel neural-fuzzy-based adaptive sliding mode automatic steering control strategy to improve the driving performance of vision-based unmanned electric vehicles with time-varying and uncertain pa...This paper presents a novel neural-fuzzy-based adaptive sliding mode automatic steering control strategy to improve the driving performance of vision-based unmanned electric vehicles with time-varying and uncertain parameters.Primarily,the kinematic and dynamic models which accurately express the steering behaviors of vehicles are constructed,and in which the relationship between the look-ahead time and vehicle velocity is revealed.Then,in order to overcome the external disturbances,parametric uncertainties and time-varying features of vehicles,a neural-fuzzy-based adaptive sliding mode automatic steering controller is proposed to supervise the lateral dynamic behavior of unmanned electric vehicles,which includes an equivalent control law and an adaptive variable structure control law.In this novel automatic steering control system of vehicles,a neural network system is utilized for approximating the switching control gain of variable structure control law,and a fuzzy inference system is presented to adjust the thickness of boundary layer in real-time.The stability of closed-loop neural-fuzzy-based adaptive sliding mode automatic steering control system is proven using the Lyapunov theory.Finally,the results illustrate that the presented control scheme has the excellent properties in term of error convergence and robustness.展开更多
Based on the traditional active steering system, a novel active steering system integrated with electric power steering function was introduced, which can achieve the functions of both active steering and electric pow...Based on the traditional active steering system, a novel active steering system integrated with electric power steering function was introduced, which can achieve the functions of both active steering and electric power steering. In view of the interference from road random signal and sensor noise in the novel active steering system, the H∞ control model of the novel active steering system was built. With satisfying steering feel, good robust performance and steering stability being the control objectives, the H∞ controller for the novel active front steering (AFS) system was designed. The simulation results show that the novel AFS system with H∞ control strategy can attenuate the road interference quickly, and there is no resonance peak in the bode diagram. It can make the driver obtain more useful information in the low frequency range, and attenuate the road interference better in the high frequency range, thus the driver can get more satisfying road feeling. Therefore, the designed H∞ controller can synthesize the advantages of both robust performance and robust stability, and has certain contribution to the design of novel AFS system.展开更多
The dynanaic model of a novel electric power steering(EPS) system integrated with active front steer- ing function and the three-freedom steering model are built. Based on these models, the concepts and the quanti- ...The dynanaic model of a novel electric power steering(EPS) system integrated with active front steer- ing function and the three-freedom steering model are built. Based on these models, the concepts and the quanti- tative expressions of road feel, sensitivity, and operation stability of the steering are introduced. Then, according to constrained optimization features of multi-variable function, a genetic algorithm is designed. Making the road feel of the steering as optimization objective, and operation stability and sensitivity of the steering as constraints, the system parameters are optimized by the genetic and the coordinate rotation algorithms. Simulation results show that the optimization of the novel EPS system by the genetic algorithm can effectively improve the road feel, thus providing a theoretical basis for the design and optimization of the novel EPS system.展开更多
Pressure ripples in electric power steering (EPS) systems can be caused by the phase lag between the driver s steering torque and steer angle, the nonlinear frictions, and the disturbances from road and sensor noise...Pressure ripples in electric power steering (EPS) systems can be caused by the phase lag between the driver s steering torque and steer angle, the nonlinear frictions, and the disturbances from road and sensor noise especially during high-frequency maneuvers. This paper investigates the use of the robust fuzzy control method for actively reducing pressure ripples for EPS systems. Remarkable progress on steering maneuverability is achieved. The EPS dynamics is described with an eight-order nonlinear state-space model and approximated by a Takagi-Sugeno (T-S) fuzzy model with time-varying delays and external disturbances. A stabilization approach is then presented for nonlinear time-delay systems through fuzzy state feedback controller in parallel distributed compensation (PDC) structure. The closed-loop stability conditions of EPS system with the fuzzy controller are parameterized in terms of the linear matrix inequality (LMI) problem. Simulations and experiments using the proposed robust fuzzy controller and traditional PID controller have been carried out for EPS systems. Both the simulation and experiment results show that the proposed fuzzy controller can reduce the torque ripples and allow us to have a good steering feeling and stable driving.展开更多
Electric load simulator(ELS) systems are employed for electric power steering(EPS) test benches to load rack force by precise control. Precise ELS control is strongly influenced by nonlinear factors. When the steering...Electric load simulator(ELS) systems are employed for electric power steering(EPS) test benches to load rack force by precise control. Precise ELS control is strongly influenced by nonlinear factors. When the steering motor rapidly rotates, extra force is directly superimposed on the original static loading error, which becomes one of the main sources of the final error. It is key to achieve ELS precise loading control for the entire EPS test bench. Therefore, a three-part compound control algorithm is proposed to improve the loading accuracy. First, a fuzzy proportional–integral plus feedforward controller with force feedback is presented. Second, a friction compensation algorithm is established to reduce the influence of friction. Then, the relationships between each quantity and the extra force are analyzed when the steering motor rapidly rotates, and a net torque feedforward compensation algorithm is proposed to eliminate the extra force. The compound control algorithm was verified through simulations and experiments. The results show that the tracking performance of the compound control algorithm satisfies the demands of engineering practice, and the extra force in the ELS system can be suppressed by the net torque corresponding to the actuator’s acceleration.展开更多
The dynamic model of a novel electric power steering (EPS) system integrated with active front steering function (the novel EPS system) is built. The concepts and quantitative expressions of the steering road feel...The dynamic model of a novel electric power steering (EPS) system integrated with active front steering function (the novel EPS system) is built. The concepts and quantitative expressions of the steering road feel, steering sensibility, and steering operation stability are introduced. Based on quality engineering theory, the optimization algorithm is proposed by integrating the Monte Carlo descriptive sampling, elitist non-dominated sorting genetic algorithm (NSGA-II) and 6-sigma design method. With the steering road feel and the steering portability as optimization targets, the system parameters are optimized by the proposed optimization algorithm. The simulation results show that the system optimized based on quality engineering theory 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 novel electric power steering system.展开更多
The vehicle model of the recirculating ball-type electric power steering (EPS) system for the pure electric bus was built. According to the features of constrained optimization for multi-variable function, a multi-obj...The vehicle model of the recirculating ball-type electric power steering (EPS) system for the pure electric bus was built. According to the features of constrained optimization for multi-variable function, a multi-objective genetic algorithm (GA) was designed. Based on the model of system, the quantitative formula of the road feel, sensitivity, and operation stability of the steering were induced. Considering the road feel and sensitivity of steering as optimization objectives, and the operation stability of steering as constraint, the multi-objective GA was proposed and the system parameters were optimized. The simulation results show that the system optimized by multi-objective genetic algorithm has better road feel, steering sensibility and steering stability. The energy of steering road feel after optimization is 1.44 times larger than the one before optimization, and the energy of portability after optimization is 0.4 times larger than the one before optimization. The ground test was conducted in order to verify the feasibility of simulation results, and it is shown that the pure electric bus equipped with the recirculating ball-type EPS system can provide better road feel and better steering portability for the drivers, thus the optimization methods can provide a theoretical basis for the design and optimization of the recirculating ball-type EPS system.展开更多
With penetration growing of renewable energy sources which integrated into power system have caused problems on grid stability. Electric Vehicles (EV) are one of the renewable energy sources that can bring significant...With penetration growing of renewable energy sources which integrated into power system have caused problems on grid stability. Electric Vehicles (EV) are one of the renewable energy sources that can bring significant impacts to power system during their charging and discharging operations. This article established a model of single machine infinite bus (SMIB) power system considering EV as a case study of load disturbance for power system oscillation. The objective of this research is to enhance stability and overcome the drawbacks of traditional control algorithms such as power system stabilizer (PSS), PID controller and fuzzy logic controller (FLC). The implementation’s effect of FLC parallel with PID controller (Fuzzy-PID) has been shown in this paper. The speed deviation (?ω) and electrical power (Pe) are the important factors to be taken into consideration without EV (only change in mechanical torque), EV with change in the mechanical torque and sudden plug-in EV. The obtained result by nonlinear simulation using Matlab/Simulink of a SMIB power system with EV has shown the effectiveness of using (Fuzzy-PID) against all disturbances.展开更多
The tracking performance of motor current is an important factor that affects the assistance torque of electric power steering (EPS) system. Bad tracking performance will cause assistant torque delay, and make road ...The tracking performance of motor current is an important factor that affects the assistance torque of electric power steering (EPS) system. Bad tracking performance will cause assistant torque delay, and make road feeling bad, and is influenced by the input steering torque and system measuring noise. However the existing methods have some shortages on system's robust dynamic performance and robust stability. The mixed H2/H∞ strategy for recirculating ball-type EPS system in a pure electric bus is proposed, and vehicle dynamic model of the system is established. Due to the existence of system model uncertainty, disturbance signals, sensor noises and the demand of system dynamic performance, the indexes of robust performance and road feeling for drivers are defined as the appraisal control objectives. The H∞ method is introduced to design the H∞ controller, and the H2 method is applied to optimize the H∞ controller, thus the mixed H2/H∞ controller is designed. The response of EPS system to the motor current command with amplitude of 20 A, the road disturbance with amplitude of 500 N and the sensor random noise with the amplitude of 1 A is simulated. The simulation results show that the recirculating ball-type EPS system with the mixed H2/H∞ controller can attenuate the random noises and disturbances and track the boost curve well, so the mixed H2/H∞ controller can improve the system's robust performance and dynamic performance. For the purpose of verifying the performance of the designed control strategy, the motor current tracking performance ground tests are conducted with step response input of the steering wheel, double-lane steering test and lemniscate steering test, respectively. The tests show that the mixed H2/H∞ controller for the recirculating ball-type EPS system of pure electric bus is feasible. The designed controller can solve the robust performance and robust stability of the system, thus improve the tracking performance of the EPS system and provide satisfied road feeling for the drivers.展开更多
With most countries paying attention to the environment protection, hybrid electric vehicles have become a focus of automobile research and development due to the characteristics of energy saving and low emission. Pow...With most countries paying attention to the environment protection, hybrid electric vehicles have become a focus of automobile research and development due to the characteristics of energy saving and low emission. Power follower control strategy(PFCS) and DC-link voltage control strategy are two sorts of control strategies for series hybrid electric vehicles(HEVs). Combining those two control strategies is a new idea for control strategy of series hybrid electric vehicles. By tuning essential parameters which are the defined constants under DClink voltage control and under PFCS, the points of minimum mass of equivalent fuel consumption(EFC) corresponding to a series of variables are marked for worldwide harmonized light vehicles test procedure(WLTP). The fuel economy of series HEVs with the combination control schemes performs better compared with individual control scheme. The results show the effects of the combination control schemes for series HEVs driving in an urban environment.展开更多
In this paper,the case of a battery charger for electric vehicles based on a wireless power transmission is addressed.The specificity of every stage of the overall system is presented.Based on calculated and measured ...In this paper,the case of a battery charger for electric vehicles based on a wireless power transmission is addressed.The specificity of every stage of the overall system is presented.Based on calculated and measured results,relevant capacitive compensations of the transformer and models are suggested and discussed in order to best match the operating mode and aiming at simplifying as much as possible the control and the electronics of the charger.展开更多
The charger of electric vehicle is a power electronic device which consists of rectifying devices and DC-DC converters. This nonlinear diode rectifier circuit has low power factor and high harmonic content. In order t...The charger of electric vehicle is a power electronic device which consists of rectifying devices and DC-DC converters. This nonlinear diode rectifier circuit has low power factor and high harmonic content. In order to improve power factor and reduce the harmonic distortion rate of the AC side current, single-phase non-controlled rectifier charger needs to install the active power factor correction device. A piece of power system analysis software which is called PSCAD is used in modeling of an EV charger which contains Boost-APFC. By means of simulation and analysis, differences of APFC characteristics between the hysteresis current control mode and average current control mode which has an influence on the power grid are compared. The consequence of simulation shows that the two control strategies achieve power factor correction and harmonic reduction requirements;Boost type power conversion circuit employs the average current control mode is better, which has following features: relatively faster settling time of the output voltage, relatively smaller overshoot, lower current harmonic distortion rate on AC side, lower switching frequency and better control effect.展开更多
Many distribution systems operate under unbalanced loading conditions due to the connection of single phase loads to a three phase system. As PHEVs become more prevalent, it is expected that this unbalance will be fur...Many distribution systems operate under unbalanced loading conditions due to the connection of single phase loads to a three phase system. As PHEVs become more prevalent, it is expected that this unbalance will be further exacerbated due to the power draws from single phase chargers. Unbalanced loads reduce the overall system operating efficiency and power transfer capability of assets. In this paper, a new method of mitigating real power unbalance is suggested. It works by selecting which of the three phases that each single phase PHEV charger in a car park should be connected to. The algorithm is then tested on a simulation model of a real world distribution system. Using the balancing algorithm, balancing of the real power flowing through the feeder to the car park is accomplished.展开更多
There are lots of factors that can influence the wireless charging efficiency in practice, such as misalignment and air-gap difference, which can also change all the charging parameters. To figure out the relationship...There are lots of factors that can influence the wireless charging efficiency in practice, such as misalignment and air-gap difference, which can also change all the charging parameters. To figure out the relationship between those facts and system, this paper presents a serial-parallel compensated(SPC) topology for electric vehicle/plug-in hybrid electric vehicle(EV/PHEV) wireless charger and provides all the parameters changing with corresponding curves. An ANSYS model is built to extract the coupling coefficient of coils. When the system is works at constant output power, the scan frequency process can be applied to wireless power transfer(WPT) and get the resonant frequency. In this way, it could determine the best frequency for system to achieve zero voltage switching status and force the system to hit the maximum transmission efficiency. Then frequency tracking control(FTC) is used to obtain the highest system efficiency. In the paper, the designed system is rated at 500 W with 15 cm air-gap, the overall efficiency is 92%. At the end, the paper also gives the consideration on how to improve the system efficiency.展开更多
Many existing studies seek to examine and mitigate possible impacts which plug in vehicle (PEV) charging will have on electric utilities. As PEVs increase in popularity, car parks will have to be built in order to all...Many existing studies seek to examine and mitigate possible impacts which plug in vehicle (PEV) charging will have on electric utilities. As PEVs increase in popularity, car parks will have to be built in order to allow for charging while away from home. Existing studies fail to consider the unbalance conditions in the distribution feeders to car parks during PEV charging. This paper presents an innovative idea to improve the unbalance conditions caused by a car park by reconfiguring PEV charger connections to a three-phase system. Although the developed algorithm is simple, results show its ability to balance the power among the phases. A car park is used as an example to show that balancing of the real power drawn by PEV chargers in a parking structure is a success.展开更多
A novel electric power steering system(EPS) integrated with active front steering(AFS) is developed.It has functions of both AFS system and EPS system with two actuator units:the AFS actuator unit and the EPS actuator...A novel electric power steering system(EPS) integrated with active front steering(AFS) is developed.It has functions of both AFS system and EPS system with two actuator units:the AFS actuator unit and the EPS actuator unit.The AFS actuator unit controls the displacement transfer behavior of the steering system,and improves the handling stability under adverse road conditions by varying the steering ratio directly related to the speed and road conditions.The EPS actuator unit controls the force transfer behavior of the steering system,and improves the steering portability and road feel of the vehicle.Based on a dynamic model,the mixed H2/H∞ control strategy of the EPS actuator and the active steering intervention control strategy of the AFS actuator are designed.The simulation indicates that the novel EPS system with the designed control strategies has obvious advantages in vehicle handling stability and the driver's road feel over the traditional EPS system,and extends the vehicle's steering performance.展开更多
With the increasing integration of wind farms and electric vehicles(EVs)in power systems,voltage stability is becoming more and more serious.Based on vehicle-to-grid(V2G),an efficient power plant model of EVs(E-EPP)wa...With the increasing integration of wind farms and electric vehicles(EVs)in power systems,voltage stability is becoming more and more serious.Based on vehicle-to-grid(V2G),an efficient power plant model of EVs(E-EPP)was developed to estimate EV charging load with available corresponding response capacity under different charging strategies.A preventive control strategy based on E-EPP was proposed to maintain the static voltage stability margin(VSM)of power system above a predefined security level.Two control modes were used including the disconnection of EV charging load(‘V1G’mode)and the discharge of stored battery energy back to power grid(‘V2G’mode).A modified IEEE 14-bus system with high penetration of wind power and EVs was used to verify the effectiveness of preventive control strategy.Simulation results showed that the proposed strategy can not only improve the static voltage stability of power system with considerable wind generation,but also guarantee the travelling comfort for EV owners.展开更多
A pinion-type electric power steering (EPS) equipped on a sedan is reached in this paper. A three-freedom dynamic model of this system is created. The variables affecting assist character is analyzed. The formulas of ...A pinion-type electric power steering (EPS) equipped on a sedan is reached in this paper. A three-freedom dynamic model of this system is created. The variables affecting assist character is analyzed. The formulas of simpled steering resistance force and the relationship between assist gain and vehicle speed are presented for the first time. Assist character is found based on the parameters of a sedan at last. This assist character is fit for the control rule of the EPS system through analyzing this character. The assist character figure offers reference for system design and control. Furthermore, this research method has generality for assist character of different kinds of vehicles.展开更多
With the combination of engine and two electric machines, the power split device allows higher efficiency of the engine. The operation modes of a power split HEV are analyzed, and the system dynamic model is establish...With the combination of engine and two electric machines, the power split device allows higher efficiency of the engine. The operation modes of a power split HEV are analyzed, and the system dynamic model is established for HEV forward simulation and controller design. Considering the fact that the operation modes of the HEV are event-driven and the system dynamics is continuous time-driven for each mode, the structure of the controller is built and described with the hybrid automaton control theory. In this control structure, the mode selection process is depicted by the finite state machine (FSM). The multi-mode switch controller is designed to realize power distribution. Furthermore, the vehicle mode operations are optimized, and the nonlinear model predictive control (NMPC) strategy is applied by implementing dynamic programming (DP) in the finite pre- diction horizon. Comparative simulation results demonstrate that the hybrid control structure is effective and feasible for HEV energy management design. The NMPC optimal strategy is superior in improving fuel economy.展开更多
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,inducti...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.展开更多
基金Supported by National Basic Research Project of China(Grant No.2016YFB0100900)National Natural Science Foundation of China(Grant No.61803319)+2 种基金Shenzhen Municipal Science and Technology Projects of China(Grant No.JCYJ20180306172720364)Fundamental Research Funds for the Central Universities of China(Grant No.20720190015)State Key Laboratory of Automotive Safety and Energy of China(Grant No.KF2011).
文摘This paper presents a novel neural-fuzzy-based adaptive sliding mode automatic steering control strategy to improve the driving performance of vision-based unmanned electric vehicles with time-varying and uncertain parameters.Primarily,the kinematic and dynamic models which accurately express the steering behaviors of vehicles are constructed,and in which the relationship between the look-ahead time and vehicle velocity is revealed.Then,in order to overcome the external disturbances,parametric uncertainties and time-varying features of vehicles,a neural-fuzzy-based adaptive sliding mode automatic steering controller is proposed to supervise the lateral dynamic behavior of unmanned electric vehicles,which includes an equivalent control law and an adaptive variable structure control law.In this novel automatic steering control system of vehicles,a neural network system is utilized for approximating the switching control gain of variable structure control law,and a fuzzy inference system is presented to adjust the thickness of boundary layer in real-time.The stability of closed-loop neural-fuzzy-based adaptive sliding mode automatic steering control system is proven using the Lyapunov theory.Finally,the results illustrate that the presented control scheme has the excellent properties in term of error convergence and robustness.
基金Foundation item: Projects(51005115, 51205191) supported by the National Natural Science Foundation of China Project(2012-NELEV-03) supported by the Research Foundation of National Engineering Laboratory for Electric Vehicles, China+2 种基金 Project(kfjj 120105) supported by the Visiting Scholar Foundation of the State Key Laboratory of Mechanical Transmission in Chongqing University, China Project supported by the Funds from the Postgraduate Creative Base in Nanjing University of Areonautics and Astronautics, China Project supported by the Fundamental Research Funds for the Central Universities, China
文摘Based on the traditional active steering system, a novel active steering system integrated with electric power steering function was introduced, which can achieve the functions of both active steering and electric power steering. In view of the interference from road random signal and sensor noise in the novel active steering system, the H∞ control model of the novel active steering system was built. With satisfying steering feel, good robust performance and steering stability being the control objectives, the H∞ controller for the novel active front steering (AFS) system was designed. The simulation results show that the novel AFS system with H∞ control strategy can attenuate the road interference quickly, and there is no resonance peak in the bode diagram. It can make the driver obtain more useful information in the low frequency range, and attenuate the road interference better in the high frequency range, thus the driver can get more satisfying road feeling. Therefore, the designed H∞ controller can synthesize the advantages of both robust performance and robust stability, and has certain contribution to the design of novel AFS system.
基金Supported by the National Natural Science Foundation of China(51005115)the Risiting Scholar Foundation of the State Key Lab of Mechanical Transmission in Chongqing University(SKLMT-KFKT-201105)theScience Fund of State Key Laboratory of Automotive Satefy and Energy in Tsinghua University(KF11202)~~
文摘The dynanaic model of a novel electric power steering(EPS) system integrated with active front steer- ing function and the three-freedom steering model are built. Based on these models, the concepts and the quanti- tative expressions of road feel, sensitivity, and operation stability of the steering are introduced. Then, according to constrained optimization features of multi-variable function, a genetic algorithm is designed. Making the road feel of the steering as optimization objective, and operation stability and sensitivity of the steering as constraints, the system parameters are optimized by the genetic and the coordinate rotation algorithms. Simulation results show that the optimization of the novel EPS system by the genetic algorithm can effectively improve the road feel, thus providing a theoretical basis for the design and optimization of the novel EPS system.
基金supported Foundation of National Development and Reform Commission of China (No. 2040)
文摘Pressure ripples in electric power steering (EPS) systems can be caused by the phase lag between the driver s steering torque and steer angle, the nonlinear frictions, and the disturbances from road and sensor noise especially during high-frequency maneuvers. This paper investigates the use of the robust fuzzy control method for actively reducing pressure ripples for EPS systems. Remarkable progress on steering maneuverability is achieved. The EPS dynamics is described with an eight-order nonlinear state-space model and approximated by a Takagi-Sugeno (T-S) fuzzy model with time-varying delays and external disturbances. A stabilization approach is then presented for nonlinear time-delay systems through fuzzy state feedback controller in parallel distributed compensation (PDC) structure. The closed-loop stability conditions of EPS system with the fuzzy controller are parameterized in terms of the linear matrix inequality (LMI) problem. Simulations and experiments using the proposed robust fuzzy controller and traditional PID controller have been carried out for EPS systems. Both the simulation and experiment results show that the proposed fuzzy controller can reduce the torque ripples and allow us to have a good steering feeling and stable driving.
基金Supported by National Natural Science Foundation of China (Grant No. 51505178)China Postdoctoral Science Foundation (Grant No. 2014M561289)。
文摘Electric load simulator(ELS) systems are employed for electric power steering(EPS) test benches to load rack force by precise control. Precise ELS control is strongly influenced by nonlinear factors. When the steering motor rapidly rotates, extra force is directly superimposed on the original static loading error, which becomes one of the main sources of the final error. It is key to achieve ELS precise loading control for the entire EPS test bench. Therefore, a three-part compound control algorithm is proposed to improve the loading accuracy. First, a fuzzy proportional–integral plus feedforward controller with force feedback is presented. Second, a friction compensation algorithm is established to reduce the influence of friction. Then, the relationships between each quantity and the extra force are analyzed when the steering motor rapidly rotates, and a net torque feedforward compensation algorithm is proposed to eliminate the extra force. The compound control algorithm was verified through simulations and experiments. The results show that the tracking performance of the compound control algorithm satisfies the demands of engineering practice, and the extra force in the ELS system can be suppressed by the net torque corresponding to the actuator’s acceleration.
基金Projects(51005115,51205191)supported by the National Natural Science Foundation of ChinaProject(QC201101)supported by the Visiting Scholar Foundation of the Automobile Engineering Key Laboratory of Jiangsu Province,China+1 种基金Project(SKLMT-KFKT-201105)supported by the Visiting Scholar Foundation of the State Key Laboratory of Mechanical Transmission in Chongqing University,ChinaProjects(NS2013015,NS2012086)supported by the Funds from the Postgraduate Creative Base in Nanjing University of Areonautics and Astronautics,and NUAA Research Funding,China
文摘The dynamic model of a novel electric power steering (EPS) system integrated with active front steering function (the novel EPS system) is built. The concepts and quantitative expressions of the steering road feel, steering sensibility, and steering operation stability are introduced. Based on quality engineering theory, the optimization algorithm is proposed by integrating the Monte Carlo descriptive sampling, elitist non-dominated sorting genetic algorithm (NSGA-II) and 6-sigma design method. With the steering road feel and the steering portability as optimization targets, the system parameters are optimized by the proposed optimization algorithm. The simulation results show that the system optimized based on quality engineering theory 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 novel electric power steering system.
基金Projects(51005115, 51005248) supported by the National Natural Science Foundation of ChinaProject(SKLMT-KFKT-201105)supported by the Visiting Scholar Foundation of State Key Laboratory of Mechanical Transmission in Chongqing University, ChinaProject(QC201101) supported by Visiting Scholar Foundation of the Automobile Engineering Key Laboratory of Jiangsu Province, China
文摘The vehicle model of the recirculating ball-type electric power steering (EPS) system for the pure electric bus was built. According to the features of constrained optimization for multi-variable function, a multi-objective genetic algorithm (GA) was designed. Based on the model of system, the quantitative formula of the road feel, sensitivity, and operation stability of the steering were induced. Considering the road feel and sensitivity of steering as optimization objectives, and the operation stability of steering as constraint, the multi-objective GA was proposed and the system parameters were optimized. The simulation results show that the system optimized by multi-objective genetic algorithm has better road feel, steering sensibility and steering stability. The energy of steering road feel after optimization is 1.44 times larger than the one before optimization, and the energy of portability after optimization is 0.4 times larger than the one before optimization. The ground test was conducted in order to verify the feasibility of simulation results, and it is shown that the pure electric bus equipped with the recirculating ball-type EPS system can provide better road feel and better steering portability for the drivers, thus the optimization methods can provide a theoretical basis for the design and optimization of the recirculating ball-type EPS system.
文摘With penetration growing of renewable energy sources which integrated into power system have caused problems on grid stability. Electric Vehicles (EV) are one of the renewable energy sources that can bring significant impacts to power system during their charging and discharging operations. This article established a model of single machine infinite bus (SMIB) power system considering EV as a case study of load disturbance for power system oscillation. The objective of this research is to enhance stability and overcome the drawbacks of traditional control algorithms such as power system stabilizer (PSS), PID controller and fuzzy logic controller (FLC). The implementation’s effect of FLC parallel with PID controller (Fuzzy-PID) has been shown in this paper. The speed deviation (?ω) and electrical power (Pe) are the important factors to be taken into consideration without EV (only change in mechanical torque), EV with change in the mechanical torque and sudden plug-in EV. The obtained result by nonlinear simulation using Matlab/Simulink of a SMIB power system with EV has shown the effectiveness of using (Fuzzy-PID) against all disturbances.
基金supported by National Natural Science Foundation of China (Grant No. 51005115, No. 51005248)Science Fund of State Key Laboratory of Automotive Safety and Energy of China (Grant No. KF11201)
文摘The tracking performance of motor current is an important factor that affects the assistance torque of electric power steering (EPS) system. Bad tracking performance will cause assistant torque delay, and make road feeling bad, and is influenced by the input steering torque and system measuring noise. However the existing methods have some shortages on system's robust dynamic performance and robust stability. The mixed H2/H∞ strategy for recirculating ball-type EPS system in a pure electric bus is proposed, and vehicle dynamic model of the system is established. Due to the existence of system model uncertainty, disturbance signals, sensor noises and the demand of system dynamic performance, the indexes of robust performance and road feeling for drivers are defined as the appraisal control objectives. The H∞ method is introduced to design the H∞ controller, and the H2 method is applied to optimize the H∞ controller, thus the mixed H2/H∞ controller is designed. The response of EPS system to the motor current command with amplitude of 20 A, the road disturbance with amplitude of 500 N and the sensor random noise with the amplitude of 1 A is simulated. The simulation results show that the recirculating ball-type EPS system with the mixed H2/H∞ controller can attenuate the random noises and disturbances and track the boost curve well, so the mixed H2/H∞ controller can improve the system's robust performance and dynamic performance. For the purpose of verifying the performance of the designed control strategy, the motor current tracking performance ground tests are conducted with step response input of the steering wheel, double-lane steering test and lemniscate steering test, respectively. The tests show that the mixed H2/H∞ controller for the recirculating ball-type EPS system of pure electric bus is feasible. The designed controller can solve the robust performance and robust stability of the system, thus improve the tracking performance of the EPS system and provide satisfied road feeling for the drivers.
基金supported in part by the National Natural Science Foundation of China(61773382,61773381,61533019)Chinese Guangdongs S&T projects(2016B090910001,2017B090912001)+1 种基金2016 S&T Benefiting Special Project(16-6-2-62-nsh)of Qingdao Achievements Transformation ProgramDongguan Innovation Talents Project(Gang Xiong)
文摘With most countries paying attention to the environment protection, hybrid electric vehicles have become a focus of automobile research and development due to the characteristics of energy saving and low emission. Power follower control strategy(PFCS) and DC-link voltage control strategy are two sorts of control strategies for series hybrid electric vehicles(HEVs). Combining those two control strategies is a new idea for control strategy of series hybrid electric vehicles. By tuning essential parameters which are the defined constants under DClink voltage control and under PFCS, the points of minimum mass of equivalent fuel consumption(EFC) corresponding to a series of variables are marked for worldwide harmonized light vehicles test procedure(WLTP). The fuel economy of series HEVs with the combination control schemes performs better compared with individual control scheme. The results show the effects of the combination control schemes for series HEVs driving in an urban environment.
文摘In this paper,the case of a battery charger for electric vehicles based on a wireless power transmission is addressed.The specificity of every stage of the overall system is presented.Based on calculated and measured results,relevant capacitive compensations of the transformer and models are suggested and discussed in order to best match the operating mode and aiming at simplifying as much as possible the control and the electronics of the charger.
文摘The charger of electric vehicle is a power electronic device which consists of rectifying devices and DC-DC converters. This nonlinear diode rectifier circuit has low power factor and high harmonic content. In order to improve power factor and reduce the harmonic distortion rate of the AC side current, single-phase non-controlled rectifier charger needs to install the active power factor correction device. A piece of power system analysis software which is called PSCAD is used in modeling of an EV charger which contains Boost-APFC. By means of simulation and analysis, differences of APFC characteristics between the hysteresis current control mode and average current control mode which has an influence on the power grid are compared. The consequence of simulation shows that the two control strategies achieve power factor correction and harmonic reduction requirements;Boost type power conversion circuit employs the average current control mode is better, which has following features: relatively faster settling time of the output voltage, relatively smaller overshoot, lower current harmonic distortion rate on AC side, lower switching frequency and better control effect.
文摘Many distribution systems operate under unbalanced loading conditions due to the connection of single phase loads to a three phase system. As PHEVs become more prevalent, it is expected that this unbalance will be further exacerbated due to the power draws from single phase chargers. Unbalanced loads reduce the overall system operating efficiency and power transfer capability of assets. In this paper, a new method of mitigating real power unbalance is suggested. It works by selecting which of the three phases that each single phase PHEV charger in a car park should be connected to. The algorithm is then tested on a simulation model of a real world distribution system. Using the balancing algorithm, balancing of the real power flowing through the feeder to the car park is accomplished.
基金Department of Technology in Shaanxi Province,China(No.2016GY-126)
文摘There are lots of factors that can influence the wireless charging efficiency in practice, such as misalignment and air-gap difference, which can also change all the charging parameters. To figure out the relationship between those facts and system, this paper presents a serial-parallel compensated(SPC) topology for electric vehicle/plug-in hybrid electric vehicle(EV/PHEV) wireless charger and provides all the parameters changing with corresponding curves. An ANSYS model is built to extract the coupling coefficient of coils. When the system is works at constant output power, the scan frequency process can be applied to wireless power transfer(WPT) and get the resonant frequency. In this way, it could determine the best frequency for system to achieve zero voltage switching status and force the system to hit the maximum transmission efficiency. Then frequency tracking control(FTC) is used to obtain the highest system efficiency. In the paper, the designed system is rated at 500 W with 15 cm air-gap, the overall efficiency is 92%. At the end, the paper also gives the consideration on how to improve the system efficiency.
文摘Many existing studies seek to examine and mitigate possible impacts which plug in vehicle (PEV) charging will have on electric utilities. As PEVs increase in popularity, car parks will have to be built in order to allow for charging while away from home. Existing studies fail to consider the unbalance conditions in the distribution feeders to car parks during PEV charging. This paper presents an innovative idea to improve the unbalance conditions caused by a car park by reconfiguring PEV charger connections to a three-phase system. Although the developed algorithm is simple, results show its ability to balance the power among the phases. A car park is used as an example to show that balancing of the real power drawn by PEV chargers in a parking structure is a success.
基金supported by the National Natural Science Foundation of China (Grant Nos 51005115, 51005248)the Science Fund of State Key Laboratory of Automotive Safety and Energy (Grant No KF11201)NUAA Research Funding (Grant No NS2010058)
文摘A novel electric power steering system(EPS) integrated with active front steering(AFS) is developed.It has functions of both AFS system and EPS system with two actuator units:the AFS actuator unit and the EPS actuator unit.The AFS actuator unit controls the displacement transfer behavior of the steering system,and improves the handling stability under adverse road conditions by varying the steering ratio directly related to the speed and road conditions.The EPS actuator unit controls the force transfer behavior of the steering system,and improves the steering portability and road feel of the vehicle.Based on a dynamic model,the mixed H2/H∞ control strategy of the EPS actuator and the active steering intervention control strategy of the AFS actuator are designed.The simulation indicates that the novel EPS system with the designed control strategies has obvious advantages in vehicle handling stability and the driver's road feel over the traditional EPS system,and extends the vehicle's steering performance.
基金This work was supported in part by the National Natural Science Foundation of China(collaborating with EPSRC of UK)(Nos.51361130152 and EP/L001039/1)the National Science and Technology Support Program of China(No.2013BAA01B03)Research on Reactive Power Control and Comprehensive Evaluation Technique of Large Scale Integration of Wind/Photovoltaic Power Generation(No.NY71-14-035).
文摘With the increasing integration of wind farms and electric vehicles(EVs)in power systems,voltage stability is becoming more and more serious.Based on vehicle-to-grid(V2G),an efficient power plant model of EVs(E-EPP)was developed to estimate EV charging load with available corresponding response capacity under different charging strategies.A preventive control strategy based on E-EPP was proposed to maintain the static voltage stability margin(VSM)of power system above a predefined security level.Two control modes were used including the disconnection of EV charging load(‘V1G’mode)and the discharge of stored battery energy back to power grid(‘V2G’mode).A modified IEEE 14-bus system with high penetration of wind power and EVs was used to verify the effectiveness of preventive control strategy.Simulation results showed that the proposed strategy can not only improve the static voltage stability of power system with considerable wind generation,but also guarantee the travelling comfort for EV owners.
文摘A pinion-type electric power steering (EPS) equipped on a sedan is reached in this paper. A three-freedom dynamic model of this system is created. The variables affecting assist character is analyzed. The formulas of simpled steering resistance force and the relationship between assist gain and vehicle speed are presented for the first time. Assist character is found based on the parameters of a sedan at last. This assist character is fit for the control rule of the EPS system through analyzing this character. The assist character figure offers reference for system design and control. Furthermore, this research method has generality for assist character of different kinds of vehicles.
基金supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the National Natural Science Foundation of China(Grant Nos.51475213&51305167)the Scientific Research Innovation Projects of Jiangsu Province(Grant No.KYLX_1022)
文摘With the combination of engine and two electric machines, the power split device allows higher efficiency of the engine. The operation modes of a power split HEV are analyzed, and the system dynamic model is established for HEV forward simulation and controller design. Considering the fact that the operation modes of the HEV are event-driven and the system dynamics is continuous time-driven for each mode, the structure of the controller is built and described with the hybrid automaton control theory. In this control structure, the mode selection process is depicted by the finite state machine (FSM). The multi-mode switch controller is designed to realize power distribution. Furthermore, the vehicle mode operations are optimized, and the nonlinear model predictive control (NMPC) strategy is applied by implementing dynamic programming (DP) in the finite pre- diction horizon. Comparative simulation results demonstrate that the hybrid control structure is effective and feasible for HEV energy management design. The NMPC optimal strategy is superior in improving fuel economy.
文摘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.