The electric vehicle with passive hybridization of fuel cells and supercapacitors leads to lower cost and compactness due to the absence of dc–dc converters. This article models such a vehicle and evaluates the energy efficiency of its powertrain system. The powertrain component losses, as functions of electric machine torque, speed and dc-link voltage, are modeled with a high level of detail, which are verified against available test data. Compared to a pure fuel cell system, the fuel cell efficiency is higher when supercapacitors are introduced under pulse current load, and it is higher at lower current amplitude. As the pulse current frequency increases, the fuel cell efficiency also increases due to higher proportional current from the high-efficiency supercapacitors. A multiplicity of drive cycles is selected, divided into a low, middle, and high-speed category to analyze the powertrain efficiency. The total powertrain energy efficiency varies between 53%–71% during propulsion for the studied drive cycles, whereas it is higher during braking ranging from 84% to 94%. The differences are closely related to the speed, acceleration, and dc-link voltage levels. The lower powertrain efficiency causes higher hydrogen consumption, leading to a reduced fuel cell efficiency at high speed, high acceleration, and low dc-link voltage.

中文翻译：

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燃料电池/超级电容器被动混合动力汽车系统的驱动循环能效

由于没有 dc-dc 转换器，具有燃料电池和超级电容器被动混合的电动汽车可降低成本和紧凑性。本文对此类车辆进行建模并评估其动力总成系统的能源效率。作为电机扭矩、速度和直流母线电压的函数的动力总成部件损耗采用高度详细的建模，并根据可用的测试数据进行了验证。与纯燃料电池系统相比，在脉冲电流负载下引入超级电容器时燃料电池效率更高，在较低电流幅值下效率更高。随着脉冲电流频率的增加，由于来自高效超级电容器的更高比例电流，燃料电池效率也增加。选择多个驱动循环，分为低、中、和高速类别来分析动力总成效率。在所研究的驱动循环的推进过程中，总动力系统能源效率在 53% 到 71% 之间变化，而在制动期间则更高，范围从 84% 到 94%。这些差异与速度、加速度和直流母线电压水平密切相关。较低的动力系统效率会导致较高的氢消耗，从而导致在高速、高加速度和低直流链路电压下燃料电池效率降低。