1、PDF外文：http:/ 1.英文原始资料 An actively controlled fuel cell/battery hybrid to meet pulsed power demands Abstract This paper presents the experimental results of an actively controlled fuel cell/battery hybrid power source topology that can be widely used in many applications, such as po
2、rtable electronic devices, communication equipment, spacecraft power systems, and electric vehicles,in which the power demand is impulsive rather than constant. A step-down DC/DC power converter is incorporated to actively control the power flow between the fuel cell and the battery to achieve both
3、high power and high energy densities. The results show that the hybrid power source can achieve much greater specific power and power density than the fuel cell alone. This paper first demonstrates that an actively controlled hybrid with a 35Whydrogen-fueled polymer electrolyte membrane fuel cell an
4、d a lithium-ion battery pack of six cells yielded a peak power of 100W, about three times as high as the fuel cell alone can supply, while causing a very limited (10%) weight increase to the whole system. After that, another hybrid source using a different battery array (eight cells) was investigate
5、d to further validate the control strategy and to show the flexibility and generality of the hybrid source design. The experimental data show that the hybrid source using an eight-cell battery supplied a peak power of 135W, about four times that of the fuel cell alone. Finally, three power sources i
6、ncluding the fuel cell alone and the two hybrids studied were compared in terms of specific power, power density, volume, weight, etc. The design presented here can be scaled to larger or smaller power capacities for a variety of applications. 2003 Elsevier B.V. All rights reserved. Keywords: Hybrid
7、 power source； Lithium-ion battery； Polymer electrolyte membrane fuel cell； Power converter 1. Introduction Many applications, such as portable electronic devices,communication equipment, spacecraft power systems, and electric vehicles, have a common characteristic in their load profiles. That
8、 is, they have a high ratio of peak power to average power. Fuel cells (e.g. PEM fuel cells) are considered to be the most promising alternatives among next generation energy devices due to their high energy density and clean energy 1,2. However, limited by their inherent characteristics, fuel cells
9、 have a long start-up time (usually several minutes) and poor response to instantaneous power demands. Compared with fuel cells, lithium rechargeable batteries have a rapid transient response without any warm up or start up time, and their specific power capability is also much higher than that of f
10、uel cells. Combining fuel cells with batteries yields hybrid power sources that make the best use of the advantages of each individual device and may meet the requirements for the above mentioned applications regarding both high power and high energy densities3,4. In such a hybrid fuel cell/battery
11、power source, the fuel cell is controlled to satisfy load average power requirements over a long term； the battery, on the other hand, is used to serve high pulse power requirements in short intervals.Clearly, the load time-averaged power should be less than or equal to the fuel cell rated power cap
12、ability, otherwise the battery will eventually become exhausted. This paper mainly presents the experimental study of an actively controlled fuel cell/battery hybrid serving a pulse load. In contrast to a passive hybrid, where the fuel cell is connected directly in parallel with the battery, a
13、n active hybrid has several potential advantages. Consider the structure of the active hybrid shown in Fig. 1, a DC/DC power converter is incorporated between the fuel cell and the battery so that the power flow can be actively managed. In this configuration,the fuel cell is isolated from the pulse
14、load through the power converter, while the battery is not. By controlling the power converter, the fuel cell output current, the battery current and the battery voltage all can be regulated. The operating principle of the hybrid power source that is the focus of this study is described as follows:
15、during periods of low power demand, the fuel cell will be controlled to generate an average power that is sufficient to serve the load and at the same time to charge the battery； during periods of high power demand, the fuel cell will generate the rated power and the battery will be discharged at an
16、y rate (up to the safe limit) necessary to satisfy the high power requirements. Two configurations of hybrid power sources were tested in this study. Both configurations used the same fuel cell, power converter and control algorithm； the only difference between them was the battery arra
17、y size. The study results show that such fuel cell/battery hybrid power sources achieved much greater specific power than the fuel cell alone. The first hybrid power source studied, which used a six-cell battery, demonstrated a 100W peak power capability, which is three times that of the fuel cell a
18、lone. The second hybrid power source studied, which used an eight-cell battery, achieved a higher peak power of 135W. Besides the advantage of providing higher specific power, the active hybrids offered advantages of a broader range and better regulation of the output voltage, a smaller fuel cell st
19、ress, a smaller weight and volume (for a fixed peak power capability) of the system,and faster response at startup and during step changes of power demand. In the following section, the system experimental setup is detailed. Section 3 then describes the experimental tests of two configu
20、rations of active hybrids, and compares the hybrid power sources to the fuel cell alone with attention to the specific power, power density, and power source volume and weight. Finally, the conclusions are given in Section 4. The experimental system of the active fuel cell/ battery hyb
21、rid, illustrated above in Fig. 1, was built using a hydrogen-fueled polymer electrolyte membrane fuel cell manufactured by H-Power with a nominal power capacity of 35W and nominal 24V open-circuit voltage, and Sony US18650 lithium-ion batteries with a nominal capacity of 1400 mAh per cell. A step-do
22、wn DC/DC power converter was constructed using a synchronous rectifier, as shown in Fig. 2. Two MOSFETs were adopted in this construction and were operated synchronously and complementarily. Using an active switch instead of a passive diode decreases the conductance loss dramatically and thus improv
23、es the converter efficiency； therefore, this topology is more and more commonly adopted in low-voltage power supplies. A real-time digital controller (dSPACE DC1103PPC controller board) was used
