Design methodology of a combined battery-ultracapacitor energy storage unit for vehicle power management
15 Jun 2003-Vol. 1, pp 88-93
TL;DR: In this article, the authors present a methodology for determining whether an energy storage unit (ESU) should consist of only batteries, only ultracapacitors or a combination of both.
Abstract: Hybrid and electric vehicles (HEV, EV) require some form of energy storage in order to achieve load leveling or efficiently manage power flows, mainly when accelerating or decelerating. Traditionally, batteries have been used but recently ultracapacitors have become potential candidates for energy storage in HEV/EV applications. To this end, this paper first presents a methodology for determining whether an energy storage unit (ESU) should consist of only batteries, only ultracapacitors or a combination of both. An example illustrates the feasibility of the proposed ideas. Finally, the paper concludes with a cost analysis of the different ESU alternatives.
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TL;DR: In this article, an isolated three-port bidirectional dc-dc converter composed of three full-bridge cells and a high-frequency transformer is proposed, where phase shift control managing the power flow between the ports, utilization of the duty cycle control for optimizing the system behavior is discussed and the control laws ensuring the minimum overall system losses are studied.
Abstract: An isolated three-port bidirectional dc-dc converter composed of three full-bridge cells and a high-frequency transformer is proposed in this paper. Besides the phase shift control managing the power flow between the ports, utilization of the duty cycle control for optimizing the system behavior is discussed and the control laws ensuring the minimum overall system losses are studied. Furthermore, the dynamic analysis and associated control design are presented. A control-oriented converter model is developed and the Bode plots of the control-output transfer functions are given. A control strategy with the decoupled power flow management is implemented to obtain fast dynamic response. Finally, a 1.5 kW prototype has been built to verify all theoretical considerations. The proposed topology and control is particularly relevant to multiple voltage electrical systems in hybrid electric vehicles and renewable energy generation systems.
692 citations
TL;DR: This paper compares the near-optimal configurations for three topologies of vehicles: fuel-cell-battery, fuel- cell-ultracapacitor, and fuel- Cell-batteries-ULTracAPacitor to improve performance, fuel economy, and powertrain cost.
Abstract: Although many researchers have investigated the use of different powertrain topologies, component sizes, and control strategies in fuel-cell vehicles, a detailed parametric study of the vehicle types must be conducted before a fair comparison of fuel-cell vehicle types can be performed. This paper compares the near-optimal configurations for three topologies of vehicles: fuel-cell-battery, fuel-cell-ultracapacitor, and fuel-cell-battery-ultracapacitor. The objective function includes performance, fuel economy, and powertrain cost. The vehicle models, including detailed dc/dc converter models, are programmed in Matlab/Simulink for the customized parametric study. A controller variable for each vehicle type is varied in the optimization.
348 citations
Cites background or methods from "Design methodology of a combined ba..."
...Recent studies [7]–[11] have shown that the combined...
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...This phenomenon has also been noted in [6] and [7]....
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...A lot of work has been done to investigate optimal sizing and control strategies for fuel-cell–battery [9], [12]–[14], fuel-cell–ultracapacitor [9], [12], [15], [16], and fuel-cell– battery–ultracapacitor [7]–[10] vehicles....
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...In general, dc/dc converters may be used for each ESS [7]–[10] or for only the battery or the ultracapacitor....
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TL;DR: In this article, the performance of battery versus hybrid power sources is examined in terms of pulsed current load and the trade off between the topologies is the semi-active hybrid, employing only one DC-DC converter and attaining a compromising performance.
Abstract: Battery versus hybrid power sources performance is examined in the manuscript. Passive, semi-active and fully active battery–ultracapacitor hybrids show obvious superiority over battery only powered pulsed current loads. Passive hybrid is the most simple and cheap arrangement, however its uncontrolled nature results in several drawbacks during the operation. On the other hand, the fully active hybrids achieve superior performance at the expense of two DC–DC converters and the corresponding control circuitry. The trade off between the topologies is the semi-active hybrid, employing only one DC–DC converter and attaining a compromising performance. The thorough characterization of each topology and sub-topology is presented in the manuscript and design methodology is derived for a particular case of pulsed current load.
318 citations
TL;DR: It is concluded that not only should the energy storage devices of a FCHEV be sized by their power and energy requirements, but the battery lifetime should also be considered.
Abstract: Combining high-energy-density batteries and high-power-density ultracapacitors in fuel cell hybrid electric vehicles (FCHEVs) results in a high-performance, highly efficient, low-size, and light system. Often, the battery is rated with respect to its energy requirement to reduce its volume and mass. This does not prevent deep discharges of the battery, which are critical to the lifetime of the battery. In this paper, the ratings of the battery and ultracapacitors are investigated. Comparisons of the system volume, the system mass, and the lifetime of the battery due to the rating of the energy storage devices are presented. It is concluded that not only should the energy storage devices of a FCHEV be sized by their power and energy requirements, but the battery lifetime should also be considered. Two energy-management strategies, which sufficiently divide the load power between the fuel cell stack, the battery, and the ultracapacitors, are proposed. A charging strategy, which charges the energy-storage devices due to the conditions of the FCHEV, is also proposed. The analysis provides recommendations on the design of the battery and the ultracapacitor energy-storage systems for FCHEVs.
311 citations
Cites background from "Design methodology of a combined ba..."
...The fuel cell and energy-storage devices can be connected in various ways [6], [9]–[13], but it is chosen to connect each device to the bus through dc/dc converters....
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TL;DR: The simulation results indicate that ultracapacitors can more effectively assist the fuel cell to meet the vehicle power demand and help achieve a better performance and a higher fuel economy.
Abstract: This paper studies two hybrid power systems for vehicle applications: a fuel cell-battery hybrid powertrain and a fuel cell-ultracapacitor hybrid powertrain. First, the characteristics of fuel cell, battery, and ultracapacitor as power sources are summarized. Then the configurations of the two types of hybrid fuel cell powertrains are presented. Finally, example hybrid powertrains are designed and simulated using ADVISOR. The simulation results indicate that ultracapacitors can more effectively assist the fuel cell to meet the vehicle power demand and help achieve a better performance and a higher fuel economy.
240 citations
References
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01 Jun 2003
TL;DR: In this article, the authors present an analysis, design, and comparison study of several bi-directional non-isolated DC-DC converter topologies that could be considered potential candidates for the power electronic interface of HEV energy/power sources, in particular an ultracapacitor pack.
Abstract: The design of DC-DC converters for power electronic interfaces in power management systems for hybrid electric vehicle (HEV) is a very challenging task. To this end, this paper presents an analysis, design, and comparison study of several bi-directional non-isolated DC-DC converter topologies that could be considered potential candidates for the power electronic interface of HEV energy/power sources, in particular an ultracapacitor pack. The considered topologies are the half-bridge, Cuk, SEPIC, and Luo converters. The analysis and design of the converters is performed throughout equations for the stresses of the active and passive components. The comparison study, achieved by means of graphs where the variables of interest are plotted as a function of the voltage ratio Vo/Vi, uses the half-bridge converter as the base case. Particular attention is paid to the stresses of the active and passive components due to the wide input voltage requirements typical of this load-leveling or power-management application.
239 citations
01 Jan 2001
TL;DR: In this article, an optimal configuration and energy management strategy that maximizes the benefit of hybridization for a hydrogen fuel cell hybrid SUV was derived, and sensitivity to drive cycle in the optimization process was studied.
Abstract: Previous work examined degree of hybridization on the fuel economy of a hybrid electric sport utility vehicle. It was observed that not only was the vehicle control strategy important, but that its definition should be coupled with the component sizing process. Both degree of hybridization and the energy management strategy have been optimized simultaneously in this study. Simple mass scaling algorithms were employed to capture the effect of component and vehicle mass variations as a function of degree of hybridization. Additionally, the benefits of regenerative braking and power buffering have been maximized using optimization methods to determine appropriate battery pack sizing. Both local and global optimization routines were applied to improve the confidence in the solution being close to the true optimum. An optimal configuration and energy management strategy that maximizes the benefit of hybridization for a hydrogen fuel cell hybrid SUV was derived. The optimal configuration was explored, and sensitivity to drive cycle in the optimization process was studied.
106 citations
01 Jan 2000
TL;DR: In this paper, an energy storage system based on battery and supercapacitors is presented, where the properties of the proposed system are oriented in high efficiency, in a special topology with parallel channels.
Abstract: An energy storage system based on battery and supercapacitors is presented. It allows bigger amount of intantaneous power. The properties of the proposed system are oriented in high efficiency, in a special topology with parallel channels. The paper presents also an active sharing device, for equalizing the voltages across a series connection of supercapacitor. Based on a buck-boost topology, this device ensures an optimal value for the stored energy, with a high equalizingciency.
91 citations
01 Jan 2003
TL;DR: In this article, the authors extended a design methodology for a combined battery-ultracapacitor energy storage unit (BU-ESU) for vehicle power management into two areas.
Abstract: This paper extends a design methodology for a combined battery-ultracapacitor energy storage unit (BU-ESU) for vehicle power management into two areas. First, the model of the half-bridge converter replaces the generic models of the dc/dc converters used in the BU-ESU. This model is capable of determining the electric stresses present on the active and passive components during the operation of the vehicle. Second, an improved BU-ESU control strategy applicable to all operating conditions of the vehicle is determined. This control strategy is used to resize the BU-ESU. Finally, the vehicle fuel consumptions achieved when using this newly resized BU-ESU are compared using ADVISOR simulation results with those obtained for the BU-ESU designed in R.M. Schupbach et al. (June 2003).
91 citations
20 Oct 1994
TL;DR: In this article, a model of a hybrid car system is proposed to determine the required size of a capacitive energy storage device, and the performance requirements and parameters influencing the size of the capacitor are defined.
Abstract: New types of electric capacitors may provide, within several years, power capacitors which could be used as energy storage devices in serial hybrid electric car drives instead of a battery. This paper discusses how to determine the required size of such a capacitor used as the sole energy storage device. The performance requirements and parameters influencing the size of the capacitor are defined and a model of a hybrid car system is proposed to determine the size of the capacitor. Simulation results are presented to demonstrate the choices in selecting the capacitor size and to provide an estimate of the performance of a hybrid vehicle with capacitive energy storage.
18 citations