Search Results

Abstract The steering centers of four wheels for passenger car do not coincide, which may result in tire wear and the unharmoniously movement of the vehicle. In this article, an optimization control method for Four Wheel Independent Steering (4WIS) electric vehicle based on the coincidence degree of steering centers is proposed, to improve the driving performance. The nonlinear vehicle model of the four-wheel independent steering vehicle is established, and the formula of the wheel steering center is derived. The coincidence degree of wheel steering centers is defined as the evaluation index, to describe and evaluate the performance of the coordination for wheels’ movement. Meanwhile, the structure design of 4WIS system and the establishment of Direct-Current (DC) steering motor model are carried out, and the Model Predictive Control (MPC) controller for steering actuator is designed.

Abstract In this research, an integrated driving and braking control unit was developed for electric bikes. The unit integrates the driving and braking circuits in a module. Alternate commutation was used to design the driving and braking unit of a customized brushless direct-current hub motor (BLDCHM). The braking torque for the braking section is generated through alternating the duty cycle of the pulse-width-modulated (PWM) commands of the switching elements and phase sequence arrangement of the current conduction loops. The current conduction loops in the motor and switching elements is arranged to adjust the braking torque in a sophisticated way. The integrated design has been successfully tested in a commercialized electric bike with a BLDCHM.

Abstract To track desired slip ratios and desired longitudinal speeds at the centers of driving wheels in the curve, this article proposes a hierarchical structured electronic differential control (EDC) of rear-wheel independent-drive electric vehicle (EV). In the high-level control, a fuzzy algorithm-based coefficient is computed according to the driver’s emotional intention of acceleration. The fuzzy algorithm-based coefficient is used to correct the desired driving torque of vehicle transmitting to the medium-level control. In the medium-level control, an optimization algorithm is developed to allocate the desired torques with requirement of as much accurate yaw moment as possible by the desired driving torque of the vehicle and yaw moment. And the desired longitudinal speeds at the centers of the rear left and right wheels are corrected twice, respectively, by Ackermann steering principle, considering the slip angle of the wheel and yaw moment.

Abstract An integrated vehicle dynamics control system aiming to improve vehicle handling and stability by coordinating active front steering (AFS), direct yaw control (DYC), and electric differential system is developed in this article. First, an electric differential system for electric vehicle, composed of two sets of bi-PMS, in-wheel motors connected in parallel and supplied by a single five-leg inverter, one on the front axle and one on the rear axle, is designed. However, each set is controlled by a proposed sliding mode backstepping control, which has replaced the hysteresis controllers in the conventional direct torque control (DTC), can obviously reduce the torque ripple, and provide better speed tracking performance using sliding mode speed controllers.

Abstract In this article, an active sound generation (ASG) system is proposed to simulate engine order sound that is typically found in vehicles equipped with internal combustion engines. Based on an A-class electric SUV, a mathematical model simulating engine order sound is established, and a short-time Fourier transform and synthesis technique is implemented. An ASG hardware along with its main functional circuits is designed, and the control software is developed. The ASG system is configured based on the loudspeakers used by the vehicle’s audio system and the frequency response characteristics of the loudspeakers is obtained by testing. An interior sound design method simulating acceleration conditions is investigated in detail. The control method is formulated based on the interior noise characteristics in accordance with the engine order sound amplitude variation.

Abstract The control of electric vehicles (EVs) is ensured by the control of their in-wheel motors of electric traction chains. This article presents a new control strategy of an interior permanent-magnet synchronous motor (IPMSM) used in electric traction applications for high-speed operation, by combining maximum torque per ampere (MTPA) control at low speeds and flux-weakening (FW) control at high speeds. This strategy allows to control with high precision and independently the torque applied to each in-wheel motor while ensuring high torque at high speeds, which is important for embedded systems. IPMSMs have been considered as a potential candidate for EV applications due to their best power density and efficiency. To ensure optimal operation of the IPMSM, a key element for the stability of the EV, the concept of the proposed method leads to combine two torque control strategies and divides the torque/speed characteristics into two zones.

Abstract In recent years, active sound design (ASD) has become one of the most important research topics in the field of active sound control technology. For electric vehicles (EVs), road noise and wind noise become the dominant contributors to the interior noise level due to the elimination of internal combustion engines (ICEs). In this case, different vehicle brands tend to resemble each other in the perspective of the interior sound quality, leading to the loss of the distinctive interior sound characteristics and brand image. In order to restore the brand DNA characteristics, ASD is a viable and implementable choice to break the dilemma the next-generation EVs would confront. Sound amplitude control strategy plays a key role in drivers’ subjective perception during dynamically operating an EV equipped with an ASD system.

Abstract The present work contributes to the development of a multimachine control structure in a traction chain of an all-wheel-drive electric vehicle (EV). In addition, in electric traction where the traction systems are propelled by several electric motors, it is necessary to optimize the devices’ volumes and the embedded components. Thus, an interesting reduction can be obtained by the use of a single inverter that supplies several motors simultaneously. An electric motor integrated into each wheel is one of the most common configurations in EVs, which allows an independent four-wheel drive. In this work, we are seeking to impose independent control on each wheel motor using a multimotor solution for the drivetrain architectures of an EV. An interior permanent-magnet synchronous motor (IPMSM) was chosen as a traction motor.

Abstract It has been discussed in numerous prior studies that in-neutral coasting, or sailing, can accomplish considerable amount of fuel saving when properly used. The driving maneuver basically makes the vehicle sail in neutral gear when propulsion is unnecessary. By disengaging a clutch or shifting the gear to neutral, the vehicle may better utilize its kinetic energy by avoiding dragging from the engine side. This strategy has been carried over to series production recently in some of the vehicles on the market and has become one of the eco-mode features available in current vehicles. However, the duration of coasting must be long enough to attain more fuel economy benefit than deceleration fuel cutoff (DFCO)-which exists in all current vehicle powertrain controllers-can bring. Also, the transients during shifting back to drive gear can result in a drivability concern.

Abstract Advanced passenger vehicles are complex dynamic systems that are equipped with several actuators, possibly including differential braking, active steering, and semi-active or active suspensions. The simultaneous use of several actuators for integrated vehicle motion control has been a topic of great interest in literature. To facilitate this, a technique known as control allocation (CA) has been employed. CA is a technique that enables the coordination of various actuators of a system. One of the main challenges in the study of CA has been the representation of actuator dynamics in the optimal CA problem (OCAP). Using model predictive control allocation (MPCA), this problem has been addressed. Furthermore, the actual dynamics of actuators may vary over the lifespan of the system due to factors such as wear, lack of maintenance, etc. Therefore, it is further required to compensate for any mismatches between the actual actuator parameters and those used in the OCAP.

Abstract In this work, a three-phase integrated onboard battery charger is investigated and implemented for electric vehicle (EV) applications. A three-switch add-on interface is introduced to connect with the inverter and the motor windings, such that a two-channel interleaved boost converter is formed for the battery charging. The detailed system analysis, design methodology, and control strategy are discussed. Moreover, a simulation study is carried out to validate the effectiveness of the proposed integrated charger. As verification, a 5 kW liquid-cooled prototype is built and tested. The proposed integrated charging system achieves a power factor of 0.99, and total harmonic distortion (THD) of 4.82% at 5 kW with an efficiency of 93.2%.

Abstract A Direct Yaw-Moment Control (DYC) logic for a rear-wheel-drive electric-powered vehicle is proposed. The vehicle is a Formula SAE (FSAE) type race car, with two electric motors powering each rear wheel. Vehicle baseline balance is neutral at low speeds, for increased maneuverability, and increases understeering at high speeds (due to the aerodynamic configuration) for stability. A controller that can deal with these yaw response variations, modelling uncertainties, and vehicle nonlinear behavior at limit handling is proposed. A two-level control strategy is considered. For the upper level, yaw rate and sideslip angle are considered as feedback control variables and a cubic-error Proportional Derivative (PD) controller is proposed for the feedback control. For the lower level, a traction control algorithm is used, together with the yaw moment requirement, for torque allocation.

Abstract Current advances in connected and automated mobility claim to change driving scenarios worldwide. Nevertheless, the impact of automated mobility on the design of vehicle powertrains still need exhaustive assessment. In this article, a design methodology is proposed for BEV powertrains that integrates the consideration of vehicle-to-vehicle (V2V) connected driving. Particularly, each analyzed design solution is evaluated in standard drive cycles both as normal human-operated vehicle and as following car in automated V2V driving. The overall battery energy consumption for the latter case is evaluated by solving an optimization problem to determine off-line the most suitable vehicle speed trajectory. Remaining design requirements include vehicle maximum speed, acceleration capability, and gradeability. Obtained results aim at quantifying the amount of energy savings for V2V automated driving depending on the considered mission and BEV powertrain design.

Abstract In this work, the multicarrier strategies for the three-phase five-level inverter are used on the rotor Field-Oriented Control (FOC) of the Induction Motor (IM). The H-bridge inverter gain uses the triangular carrier technique to produce two Pulse Width Modulation (PWM) command strategies. These two PWM-based strategies, the Phase Disposition Carrier-PWM (PDC-PWM) strategies and the Phase Shifted Carrier-PWM (PSC-PWM) strategies, are compared to find the appropriate command for the designed Electric Vehicle (EV) system. The system is improved by the Fuzzy Logic Control (FLC) to refine its surveillance and to detect any possible deflection in the system. The Automatic Hook (AH) is connected to the front axle of the EV. In case of any divergence, the FLC is programmed to detect the divergence according to the temperature of the semiconductors, the current, the speed, and the trajectory and then it changes the state of the AH to make the needed correction.

Abstract This article presents a control strategy to improve the overall energy efficiency of connected and automated-hybrid electric vehicles (CA-HEV) in urban driving conditions. A forward-looking, traffic-aware, high-level decision control (HLDC) algorithm is proposed in this article, where both traffic and road information (obtained from surrounding vehicles and municipal traffic management centers through connected vehicle technologies) are utilized. The objective is to dynamically optimize the vehicle speed trajectories to reduce, and potentially eliminate, idling time at red traffic lights. The benefits include reduced unnecessary engine restart, emissions, and an improvement in the overall energy efficiency of the CA-HEV.

Abstract The surge in economic activities, in the developing nations, has resulted in rapid expansion of urban centres. This expansion of cities has caused a rapid increase in vehicular traffic, which in turn has caused deterioration of air quality. To overcome the problem of unprecedented air pollution, the governments worldwide have framed policies for faster adoption of electric vehicles. One of the major challenges faced is the development of low- cost drive for these vehicles and keeping the imports to a minimum. As a result of this, the trend is to move away from the permanent magnet-based motor technology and to use induction motor-based drivetrain. For the induction motors to be successful in electric vehicle drivetrain application, it is important to have a robust speed control algorithm. This work aims at adapting a direct torque control technique for induction motor’s speed control.

Abstract Numerous works have been carried out with perspectives to improve the energy efficiency of electric vehicle (EV) drivetrains; much of the attention has been on the design of highly efficient electric motors, power converters, and energy storage system. Besides the abovementioned factors, selection of the drivetrain configuration and control strategy also influence the efficiency and performance of EV drivetrain. The drivetrain efficiency and performance indices, such as torque ripple and total harmonic distortion (THD) of voltage and current, are sensitive to the direct current (dc)-link voltage and flux linkage values for a drivetrain control strategy. Therefore, in this work, the efficiency and the performance of two popular direct torque controlled induction motor (IM) drives are compared on the basis of adjustable dc-link voltage and flux linkage values for desired operating condition. Both these techniques are implemented on a lab scale test bed.

Abstract The Noise, Vibration, and Harshness (NVH) performance of automotive powertrain (PT) mounts involves the PT source vibration, PT mount stiffness, road input, and overall transfer path design. Like safety, performance, and durability driving dynamics, vehicle-level NVH also plays a major contributing factor for electric vehicle (EV) refinement. This article highlights the recent research on PT mounting-related NVH controls on electric cars. This work’s main contribution lies in the comparative study of the internal combustion engine (ICE)-based PT mounting and EV-based PT mounting system (PMS) with specific EV challenges. Various literature on PT mounts from the passive, semi-active, and active mounting systems are studied. The parameter optimization technique for mount stiffness and location by various research papers is summarized to understand the existing methodologies and research gap in EV application.

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