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Electric vehicle (EV) integration into the distribution system has been a topic of great interest lately due to the potential challenges that it poses. Previous works have focused on either centralized charge control or distributed charge control to solve these issues. In this paper, an adaptive voltage-feedback controller for an onboard EV charger is proposed, which, unlike other proposed methods, requires no real-time communication between the EV and the utility. This controller compares the system voltage at the point of charging with a preset reference voltage. EV charging is reduced as the system voltage approaches this reference. The reduced charging rate takes into account the EV battery state of charge (SOC) and the owner's end-of-charge time (ECT) preference. To validate the proposed control structure, extensive simulations are carried out on a distribution system with and without other voltage control mechanisms. Simulation results show that this method can eliminate system voltage violations that would otherwise be caused by EV charging while ensuring fairness among the various EVs, even with different system configurations and EV penetration levels. The proposed controller shows good performance in the presence of other voltage control devices and distributed generation units. Moreover, it can integrate with vehicle-to-grid services as the lowest level of hierarchical control. [ABSTRACT FROM PUBLISHER]

This paper presents the development of an electric-vehicle (EV) interior permanent-magnet synchronous motor (IPMSM) drive and its operation control. The power circuit of the established EV IPMSM drive consists of a two-leg interleaved bidirectional front-end dc/dc buck–boost converter and a three-phase inverter. The front-end converter can establish adjustable and boostable dc-link voltage for the motor drive to enhance its high-speed driving performance. It can also allow the battery bank to be charged from the motor during regenerative braking. Good current sharing control between converter modules and dc-link boosted voltage regulation response are preserved via the developed robust control scheme. Moreover, fast disturbance rejection response against the module fault and recovery is achieved. The comparative driving performance enhancements via dc-link voltage boosting and commutation instant tuning are conducted. Then, through proper setting and control, the established EV IPMSM drive possesses good driving performances, including starting, acceleration/deceleration, regenerative braking, and reversible operation characteristics. [ABSTRACT FROM PUBLISHER]

In this paper, a novel energy management system (EMS) for a hybrid power source in a small urban electric vehicle (EV) is presented. The problem is divided in three layers, according to the real-time needs of the system. The long-term management layer dynamically restricts the search space based on a set of rules. The short-term management layer implements the optimization strategy based on a hybrid metaheuristic approach combining particle swarm optimization (PSO) and simulated annealing (SA). The solutions to the optimal power sharing problem are used to generate the power references for the lower layer, i.e., a high-speed dc–dc controller. This controller is developed using a linear-quadratic regulator (LQR). A reduced-scale prototype has been built to analyze the performance of the energy management strategy. The results show the effectiveness of this multilayer EMS allowing to fulfill the requested performance with better source usage and much lower installed capacities. [ABSTRACT FROM PUBLISHER]

This paper deals with a control method that adapts the dc bus voltage of electric traction systems using permanent-magnet synchronous machine (PMSM) fed by bidirectional $Z$-source inverter (ZSI) or other improved topologies. This control allows reducing both the overestimation of the dc bus voltage and losses in the inverter. The sliding-mode control (SMC) method is used to control the $Z$-source converter, whereas flatness-based control is proposed to drive the actuator and generate the peak dc bus voltage reference. Flatness-based control is chosen because the actuator transients are well mastered. Extra shoot-through zero inverter states are inserted by means of implemented algorithm on a space-vector-modulation (SVM) scheme. Different short-circuit strategies are studied and compared according to constraint criteria. Both simulation and experimental results are presented and discussed to validate the proposed voltage adaptation strategy and the improvement on global efficiency. [ABSTRACT FROM AUTHOR]

This paper deals with the problem of controlling a hybrid energy storage system (HESS) for electric vehicles. The storage system consists of a fuel cell (FC), serving as the main power source, and a supercapacitor (SC), serving as an auxiliary power source. It also contains a power block for energy conversion consisting of a boost converter connected with the main source and a boost–buck converter connected with the auxiliary source. The converters share the same dc bus, which is connected to the traction motor through an inverter. These power converters must be controlled to meet the following requirements: 1) tight dc bus voltage regulation, 2) perfect tracking of the SC current to its reference, and 3) asymptotic stability of the closed-loop system. A nonlinear controller is developed, on the basis of the system nonlinear model, making use of Lyapunov stability design techniques. The latter accounts for the power converters' large-signal dynamics and for the FC nonlinear characteristics. It is demonstrated using both a formal analysis and simulations that the developed controller meets all desired objectives. [ABSTRACT FROM PUBLISHER]

In this paper, an inductor–inductor–capacitor (LLC) resonant dc–dc converter design procedure for an onboard lithium-ion battery charger of a plug-in hybrid electric vehicle (PHEV) is presented. Unlike traditional resistive load applications, the characteristic of a battery load is nonlinear and highly related to the charging profiles. Based on the features of an LLC converter and the characteristics of the charging profiles, the design considerations are studied thoroughly. The worst-case conditions for primary-side zero-voltage switching (ZVS) operation are analytically identified based on fundamental harmonic approximation when a constant maximum power (CMP) charging profile is implemented. Then, the worst-case operating point is used as the design targeted point to ensure soft-switching operation globally. To avoid the inaccuracy of fundamental harmonic approximation approach in the below-resonance region, the design constraints are derived based on a specific operation mode analysis. Finally, a step-by-step design methodology is proposed and validated through experiments on a prototype converting 400 V from the input to an output voltage range of 250–450 V at 3.3 kW with a peak efficiency of 98.2%. [ABSTRACT FROM PUBLISHER]

In this paper, a control strategy is presented for a high-performance capacitively loaded loop (LLC) multiresonant dc–dc converter in a two-stage smart charger for neighborhood electric vehicle (NEV) applications. It addresses several aspects and limitations of LLC resonant dc–dc converters in battery charging applications, such as very wide output voltage range while keeping the efficiency maximized, implementation of the current mode control at the secondary side, and optimization of burst mode operation for current regulation at very low output voltage. The proposed control scheme minimizes both low- and high-frequency current ripples on the battery while maintaining stability of the dc–dc converter, thus maximizing battery life without penalizing the volume of the charger. Experimental results are presented for a prototype unit converting 390 V from the input dc link to an output voltage range of 3–72 V dc at 650 W. The prototype achieves a peak efficiency value of 96%. [ABSTRACT FROM PUBLISHER]

This paper proposes a single-phase reconfigurable battery charger for an electric vehicle (EV) that operates in three different modes: 1) grid-to-vehicle (G2V) mode, in which the traction batteries are charged from the power grid; 2) vehicle-to-grid (V2G) mode, in which the traction batteries deliver part of the stored energy back to the power grid; and 3) traction-to-auxiliary (T2A) mode, in which the auxiliary battery is charged from the traction batteries. When connected to the power grid, the battery charger works with a sinusoidal current in the ac side, for both G2V and V2G modes, and regulates the reactive power. When the EV is disconnected from the power grid, the control algorithms are modified, and the full-bridge ac–dc bidirectional converter works as a full-bridge isolated dc–dc converter that is used to charge the auxiliary battery of the EV, avoiding the use of an additional charger to accomplish this task. To assess the behavior of the proposed reconfigurable battery charger under different operation scenarios, a 3.6-kW laboratory prototype has been developed, and experimental results are presented. [ABSTRACT FROM PUBLISHER]

This paper presents the design and control of a high-efficiency multiphase dc–dc converter for a truck auxiliary power unit (APU) fed by a fuel-cell stack. The power-stage design methodology and the operation of the designed power stage used to achieve high efficiency are described in detail. To operate the designed converter as a truck APU, the mode transfer control scheme, where smooth transitions of the voltage and current control modes are necessary, is proposed, and the current controller design procedure is described. A 5-kW four-phase dc–dc converter prototype is built with the proposed power-stage configuration, and the proposed control strategy is applied to control the dc–dc converter. The efficiency of the converter is more than 99.5% at near 10% load and above 98% from 10% to 100% load range. Simulations and experimental results are provided to verify the feasibilities of dc–dc converter operation and the proposed control strategy in the truck APU application. [ABSTRACT FROM PUBLISHER]

Plug-in hybrid electric vehicles (PHEVs) will play a vital role in future sustainable transportation systems due to their potential in terms of energy security, decreased environmental impact, improved fuel economy, and better performance. Moreover, new regulations have been established to improve the collective gas mileage, cut greenhouse gas emissions, and reduce dependence on foreign oil. This paper primarily focuses on two major thrust areas of PHEVs. First, it introduces a grid-friendly bidirectional alternating current/direct current ac/dc–dc/ac rectifier/inverter for facilitating vehicle-to-grid (V2G) integration of PHEVs. Second, it presents an integrated bidirectional noninverted buck–boost converter that interfaces the energy storage device of the PHEV to the dc link in both grid-connected and driving modes. The proposed bidirectional converter has minimal grid-level disruptions in terms of power factor and total harmonic distortion, with less switching noise. The integrated bidirectional dc/dc converter assists the grid interface converter to track the charge/discharge power of the PHEV battery. In addition, while driving, the dc/dc converter provides a regulated dc link voltage to the motor drive and captures the braking energy during regenerative braking. [ABSTRACT FROM PUBLISHER]

One of the most important research topics in drive train topologies applied to electric/hybrid vehicles is the efficiency analysis of the power train components, including the global drive efficiency. In this paper, two basic traction electric drive systems of electric/hybrid vehicles are presented and evaluated, with a special focus on the efficiency analysis. The first topology comprises a traditional pulsewidth-modulation (PWM) battery-powered inverter, whereas in the second topology, the battery is connected to a bidirectional dc–dc converter, which supplies the inverter. Furthermore, a variable-voltage control technique applied to this second topology is presented, which allows for the improvement of the drive overall performance. Some simulation results are presented, considering both topologies and a permanent-magnet synchronous motor (PMSM). An even more detailed analysis is performed through the experimental validation. Particular attention is given to the evaluation of the main drive components efficiency, including the global drive efficiency, presented in the form of efficiency maps. Other parameters such as motor voltage distortion and power factor are also considered. In addition, the comparison of the two topologies takes into account the drive operation under the motoring and regenerative-braking modes. [ABSTRACT FROM PUBLISHER]

This paper presents a high-gain boost converter (three-level converter and transformerless converter) for fuel cell (FC) vehicle applications. An original nonlinear control law based on the flatness principle for distributed dc generation is studied. Utilizing the flatness property, we propose simple solutions to the system performance and stabilization problems. The design controller parameters are straightforward and autonomous at the operating point. To validate the proposed method, a prototype FC power converter (1.2-kW three-level boost converter) is developed in the laboratory. The proposed control law is implemented with a digital estimate in a dSPACE 1104 controller card. The experimental results from the laboratory using a 1200-W and 46-A polymer electrolyte membrane FC (PEMFC) verify that this is a good control scheme. [ABSTRACT FROM PUBLISHER]

In this paper, a new control strategy, including saturation management of hybrid fuel-cell (FC)/ultracapacitor (UC) power sources, is described. First, an analysis of hybrid architectures using an FC and UCs for automotive applications is presented. Next, the model and the control strategy are described using energetic macroscopic representation (EMR). The main improvement over classical control strategies of such systems is to take into account saturation management with a dynamic reconfiguration of the energy management strategy (EMS). It includes the regenerative breaking in high state of charge (SOC) of the UC and the supply of a full power demand in low SOC of the UC. Finally, experimental results with small-scale devices show the effectiveness of the proposed control strategy using saturation management. [ABSTRACT FROM PUBLISHER]

This paper presents an energy management method in an electrical hybrid power source (EHPS) for electric vehicular applications. The method is based on the flatness control technique (FCT) and fuzzy logic control (FLC). This EHPS is composed of a fuel cell system as the main source and two energy storage sources (ESSs)—a bank of supercapacitors (SCs) and a bank of batteries (BATs)—as the auxiliary source. With this hybridization, the volume and mass of the EHPS can be reduced, because the high energy density of BAT and high power density of SC are utilized. In the proposed novel control strategy, the FCT is used to manage the energy between the main and the auxiliary sources, and the FLC is employed to share the power flow in the ESS between the SC and the BAT. The power sharing depends on the load power and the state of charge of the SC and the BAT. EHPS is controlled by the regulation of the stored electrostatic energy in the dc buses. The main property of this strategy is that the energy management in the power source is carried out with a single general control algorithm in different operating modes, consequently avoiding any algorithm commutation. An EHPS test bench has been assembled and equipped with a real-time system controller based on a dSPACE. The experimental results validate the efficiency of the proposed control strategy. [ABSTRACT FROM PUBLISHER]

This paper presents a predictive control-based fuel-cell hybrid electric vehicle system. Employing hybrid power sources, an ultracapacitor (UC), and a battery, the hybrid system maximizes the energy efficiency and protects the battery while achieving faster torque response based on predictive controllers residing in the boost converter, UC manager, and motor drive. The predictive controller implemented in the brushless dc (BLDC) motor drive improves the motor current response. Overall, the proposed hybrid system improves the dc-bus current response, and, hence, motor torque response, compared with a conventional proportional-integral (PI) controller-based system. The effectiveness of the proposed system has been verified through simulation and experiment. [ABSTRACT FROM PUBLISHER]