Dongdong Zhao

Parameter Sensitivity Analysis and Local Temperature Distribution Effect for a PEMFC System

Parameters identification and determination are important in the fuel cell model development, especially for multiphysic modeling which includes many sensitive semiempirical parameters. In this paper, the parameter sensitivities are investigated based on a well-developed 1.2-kW multiphysic proton exchange membrane fuel cell model. Moreover, to get a complete fuel cell system model, the models of auxiliaries such as the air compressor and cooling fan are developed. Through the analysis, the effect of some physical parameters on the fuel cell performance are obtained. Specifically, stack temperature is a crucial parameter which influences not only the output voltage, but also the water content in the fuel cell membrane. The influence of nonuniform distribution of temperature on the fuel cell model is discussed as well, including the end plate and local heating effects.

Analysis and control of a high voltage ratio and low stress DC-DC converter for fuel cell applications

The fuel cell systems are considered as current intensive sources with low output voltage, so power electronic converters are essential part of fuel cell applications. A dc/dc converter with high voltage ratio and low stress is developed in this paper. The inductors of the output series interleaved boost converter (OS-IBC) are interleaved in parallel at input which can reduce the input current ripple. Besides, the structure of output series can provide a high voltage ratio. A small signal ac model and the corresponding transfer function of the OS-IBC is derived as well as controller design is carried out in this paper. A series of simulation and experimental results validate the small signal ac model and the controller of the OS-IBC.

Energy optimization of a PEM fuel cell system by minimizing the parasitic consumption generated by the compressor

Air compressor which is employed to supply the oxygen to the cathode is a key component in the fuel cell system. It is also the main parasitic consumption, which consumes up to 15% of fuel cell generated power. How to find out the most efficiency operating point, thereby reduce the compressor consumption, is the research topic of this paper. Oxygen excess ratio connected both to the stack output power and compressor consumption is deemed as a adjustable parameter to optimize the net power. A optimal seeking approach is proposed to obtain the maximum output power. Compared with the lookup table method the proposed approach has the advantage of robustness eliminating affection by the working condition variations. The validity of this approach is proved by simulation results.

A Buck-Boost converter based on robust avoidance chattering sliding mode control for PEM fuel cell

In the process of power generation by hydrogen energy, the randomness of hydrogen, oxygen input and power output often appear, which puts forward higher requirements for the robust design of power converters. The inevitable chattering phenomenon do exist in the power converter based on traditional sliding mode due to its discrete control law. In order to conquer the above problems, this paper presents a novel avoidance chattering converter based on the super-twisting sliding modes. To remove the intermittent disturbance in the new energy power generation, especially in PEM fuel cell system, this paper compares the effect of the converter controlled by super-twisting sliding mode controller with the classic PI controller in a typical Buck - Boost power converter as an example. The simulation results show that: under the condition of large disturbances in input and output, the converter controlled by super-twisting sliding mode has stronger robustness.

Cathode partial pressures estimation of a proton exchange membrane fuel cell for transportation applications

Cathode partial pressures, such as the oxygen partial pressure and nitrogen partial pressure, are important performance parameters of the proton exchange membrane fuel cell. Oxygen partial pressure has a direct influence to the fuel cell output voltage. And the cathode total pressure, mainly composed of oxygen partial pressure, nitrogen partial pressure and vapor partial pressure, has to be kept at the optimal value to ensure the high efficiency of the fuel cell. Therefore, partial pressures are crucial variables which need to be appropriately controlled. However, those parameters are usually not measurable. In this paper, an extended state observer, which can effective deal with the nonlinearity and disturbance of the system is proposed. The simulation results show that this observer can accurately estimate the partial pressures.

Hardware-in-the-loop validation of an air supply method for vehicular fuel cell applications

This paper presents hardware-in-the-loop (HIL) validation of an air supply method for the fuel cell in automotive applications. A 12 kW proton exchange membrane fuel cell (PEMFC) model is developed and implemented in dSPACE. The performances of the fuel cell stack and compressor during a classic European Driving Cycle are tested. The experimental results show that the compressor consumes up to 25 % of the fuel cell generated power in the worst operating point, whereas only 4.2 % on average.