Impacts of power management on a PEMFC electric vehicle

This paper discusses the impacts of different power management strategies on a fuel-cell vehicle. The study was carried out in three steps: fuel-cell control, power management, and system integration and verification. First, we identified the models of a proton exchange membrane fuel-cell (PEMFC) and designed robust controllers to improve the PEMFC's performance and efficiency. Second, we developed two power management structures—a serial power train and a parallel power train—which consisted of the PEMFC and secondary batteries to provide sustainable power for an electric mobility scooter. Lastly, we used the scooter's driving cycles to compare the performance and efficiency of these two power trains. Then we implemented the power trains on a microprocessor for road test. Based on the results, both power trains are deemed effective in providing continuous power for driving the scooter. In addition, the serial power train, although it uses an extra battery set, is shown to be more efficient than the parallel one.     

Design and control of a PEMFC powered electric wheelchair

This paper proposes the design and control of a fuel-cell powered wheelchair. Electric wheelchairs can improve moving ability for people with walking problems. However, their traveling distances are limited by the capacity of their batteries. We designed a fuel-cell powered electric wheelchair that can be continuously operated, thereby extending the moving range. The system consisted of three subsystems: a commercial electric wheelchair, a proton exchange membrane fuel cell (PEMFC), and two secondary battery sets. The study was carried out in three parts, investigating the fuel-cell control, power management, and system integration. First, we designed multivariable robust controllers for a 500 W PEMFC system to charge the battery sets by constant voltage/current. Second, we designed a serial power management system, where the wheelchair motors were directly driven by the secondary battery sets, which in turn were charged by the PEMFC when their capacities dropped below a certain level. Lastly, we integrated the three subsystems and verified the system performance by experiments. The results confirmed the effectiveness of the PEMFC system as a way to extend the traveling distance of a motorized wheelchair.     

The development of a PEMFC hybrid power electric vehicle with automatic sodium borohydride hydrogen generation

This paper describes the development of a hybrid Proton Exchange Membrane Fuel Cell (PEMFC) electric vehicle consisting of a 3 kW PEMFC, PV arrays, secondary battery sets, and a chemical hydrogen generation system. We first integrate a hybrid PEMFC electric vehicle and design power management strategies. The on-board hydrogen generation system can provide sufficient hydrogen for continuous operation of the PEMFC, and the performance tests demonstrate the effectiveness of the integrated system in providing sustainable power for driving. We then use Matlab/SimPowerSystem? to develop a simulation model and adjust the model parameters using experimental data. The results indicated that the model can effectively predict system responses and can be used for performance evaluation. We also use the simulation model to estimate the mileage and costs of the developed electric vehicle, and we discuss the impacts of component sizes on system costs and travelling ranges.     

Fuel-cell sharing for a distributed hybrid power system

This paper investigates the benefits of sharing a proton exchange membrane fuel cell (PEMFC) in a distributed hybrid power system. The PEMFC is usually used as backup power in stationary hybrid power systems; however, in that scenario, it might be working only 2% of the time while incurring 20% of the system expenses. Therefore, this paper examines the potential of sharing a PEMFC among multiple power systems. We develop a distributed hybrid power system that comprises several immovable power stations and a fuel-cell vehicle (FCV). Each power station is equipped with solar panels and batteries, while the FCV contains a PEMFC module and can move among the stations to provide sustainable power as needed. We propose power management strategies and show that the total system costs can be significantly reduced by 10.83% and 17.89% when sharing one FCV between three and twelve power stations, respectively. We also design experiments to demonstrate the feasibility of the proposed distributed hybrid power system. In the future, the developed model can be extended to provide further cost reductions by optimizing distributed hybrid power systems with multiple FCVs.     

Experimental assessment of energy-management strategies in fuel-cell propulsion systems

The limitations of electric vehicles equipped with electrochemical batteries justify strong research interest for new solutions, based on hydrogen fuel-cell technology that are able to improve vehicle range, and reduce battery recharging time, while maintaining the crucial advantages of high efficiency and local zero emissions. The best working of a fuel-cell propulsion system, in terms of optimum efficiency and performance, is based on specific strategies of energy management, that are designed to regulate the power flows between the fuel cells, electric energy-storage systems and electric drive during the vehicle mission. An experimental study has been carried out on a small-size electric propulsion system based on a 2.5-kW proton exchange membrane fuel cell stack and a 2.5-kW electric drive. The fuel-cell system has been integrated into a powertrain comprising a dc–dc converter, a lead–acid battery pack, and brushless electric drive. The experiments are conducted on a test bench that is able to simulate the vehicle behaviour and road characteristics on specific driving cycles. The experimental runs are carried out on the European R40 driving cycle using different energy-management procedures and both dynamic performance and energy consumption are evaluated.     

Modeling,control and power management of hybrid photovoltaic fuel cells with battery bank supplying electric vehicle

In this paper, modeling, control and power management (PM) of hybrid Photovoltaic Fuel cell/Battery bank system supplying electric vehicle is presented. The HPS is used to produce energy without interruption. It consists of a photovoltaic generator (PV), a proton exchange membrane fuel cell (PEMFC), and a battery bank supplying an electric vehicle of 3 kW. In our work, PV and PEMFC systems work in parallel via DC/DC converter and the battery bank is used to store the excess of energy. The mathematical model topology and it power management of HPS with battery bank system supplying electric vehicle (EV) are the significant contribution of this paper. Obtained results under Matlab/Simulink and some experimental ones are presented and discussed.     

Remodeling of a commercial plug-in battery electric vehicle to a hybrid configuration with a PEM fuel cell

In the present research, a commercial battery-powered pure electric vehicle was suitably modified to convert it into a hybrid one integrating a PEMFC stack. The hydrogen supply system to the stack included a passive recirculation system based on a Ventury-type ejector. Besides, in order to achieve an optimum operation of the PEMFC stack, a discrete state machine model was considered in its control system. The inclusion of a rehabilitation operating mode prevented the stack from possible failures, increasing its lifetime. It was verified that for the rated operating point when supplying power to the vehicle (2.5 kW) the hydrogen consumption decreased, and the actual efficiency (47.9%) PEMFC was increased close to 1%. Field tests performed demonstrate that the range of the hybrid electric vehicle was increased by 78% when compared to the one of the original battery electric car. Also, under the tested experimental conditions in hybrid mode, 34% of the total energy demanded by the electric machine of the vehicle was supplied by the PEMFC stack.     

Design and implementation of power battery charging and discharging detection system

电动汽车的快速增长带来的动力电池安全问题日趋成为行业关注的焦点,对动力电池快速安全检测成为目前市场的需求。本工作设计了一套基于以双向逆变器为主的硬件模块和C#.NET上位机软件模块的动力电池充放电检测系统。该系统检测对象为电动汽车动力电池和梯次动力电池,其特点为快速检测和深入检测。快速性表现在两分钟内检测出电池包绝缘安全、单体一致性等问题。深入性是对单体层面的诊断,根据直流内阻检测模块得到单体OCV和直流内阻分布图从而快速对电池一致性问题做诊断。每个检测模块的数据最终生成电子检测报告,同时也保存至Excel中,用于后期进一步分析。系统运行可靠,可为在储能领域的推广应用提供一定的参考。     

Thermodynamic analysis of polymer-electrolyte-membrane fuel-cell performance under varying cooling conditions

The cooling capacity and cooling load of a fuel-cell cooling loop govern the operating temperature of the fuel-cell module and its electrical output, efficiency and other thermodynamic aspects. The aim of this work was to analyze the performance of a polymer-electrolyte-membrane fuel-cell (PEMFC) under changing cooling conditions. A back-iteration algorithm was employed to determine the operating temperature of a PEMFC for which thermodynamic performance models were developed for the entropy generation, exergy-destruction and second-law efficiency using an entropy-analysis method. Electrochemical equations for the calculation of the voltage, power and first-law efficiency of the cell were also formulated. A parametric study was performed to evaluate the effects of varying cooling conditions on the energy and exergy efficiency of the PEMFC. The parameters considered include the electric-current density governing the cooling load, the mass flow rate of the coolant and the external thermal resistance of the cooler, which together determine the cooling ability of the fuel-cell cooling loop. Their influences on operating temperature, voltage, power, energy and exergy efficiencies were numerically investigated. The results indicate that although the power output and exhaust heat of PEMFC is mainly dominated by the electric-current density, the impacts of the coolant's mass flow rate and the cooler's external thermal resistance on the voltage, energy and exergy efficiencies of PEMFC module can't be neglected. In the investigated ranges, the gross energy and exergy efficiencies increase with the cooler's external thermal resistance by 3.2% and 2.45%, and decrease with the increase in coolant's mass flow rate by 1.2% and 0.92%, respectively.     

Optimal energy management strategy of fuel-cell battery hybrid electric mining truck to achieve minimum lifecycle operation costs

Proton exchange membrane fuel cell (PEMFC) electric vehicle is an effective solution for improving fuel efficiency and onboard emissions, taking advantage of the high energy density and short refuelling time. However, the higher cost and short life of the PEMFC system and battery in an electric vehicle prohibit the fuel cell electric vehicle (FCEV) from becoming the mainstream transportation solution. The fuel efficiency-oriented energy management strategy (EMS) cannot guarantee the improvement of total operating costs. This paper proposes an EMS to minimize the overall operation costs of FCEVs, including the cost of hydrogen fuel, as well as the cost associated with the degradations of the PEMFC system and battery energy storage system (ESS). Based on the PEMFC and battery performance degradation models, their remaining useful life (RUL) models are introduced. The control parameters of the EMS are then optimized using a meta-model based global optimization algorithm. This study presents a new optimal control method for a large mining truck operating on a real closed-road operation cycle, using the combined energy efficiency and performance degradation cost measures of the PEMFC system and lithium-ion battery ESS. Simulation results showed that the proposed EMS could improve the total operating costs and the life of the FCEV.     

Road testing of a three-wheeler driven by a 5 kW PEM fuel cell in the absence and presence of batteries

The road testing and demonstration of a three-wheeler vehicle driven by a 5 kW proton exchange membrane fuel cell (PEMFC) was carried out in the absence and presence of lead acid batteries. Prior to integrating the PEMFC module and batteries in the three-wheeler, they were tested and demonstrated separately. The PEMFC module had a very fast response as the load was manually or, especially, automatically changed and it could supply a continuous power when the reactant was supplied continuously. In contrast, the 5 kW lead acid batteries alone could supply power for no longer than 300 s. In the presence of both the PEMFC module and batteries, when the drawing power was in the range of the PEMFC module capacity the propulsion motor gained its energy from the PEMFC module only, whilst the stack power output at all conditions was greater than the setting power of approximately 400 W. After integrating the PEMFC module and batteries into the three-wheeler, both energy sources were found to power the vehicle effectively. The motor power as well as the stack power changed as a linear proportion to the throttle. The motor consumed more power in case of high speed driving, take off or hill climbing, while it used only 0.354 kW in the absence of throttle. The hybrid system can achieve a maximum speed in this three-wheeler of around 24.9 km/h with a hydrogen consumption of 11 g H₂/km (71 g H₂/kWh) and an operating cost of 1.99 USD/km. The thermodynamic efficiency of the vehicle was 42.9%.     

Energy management of a fuel cell/ultracapacitor hybrid power system using an adaptive optimal-control method

Energy management of a fuel cell/ultracapacitor hybrid power system aims to optimize energy efficiency while satisfying the operational constraints. The current challenges include ensuring that the non-linear dynamics and energy management of a hybrid power system are consistent with state and input constraints imposed by operational limitations. This paper formulates the requirements for energy management of the hybrid power system as a constrained optimal-control problem, and then transforms the problem into an unconstrained form using the penalty-function method. Radial-basis-function networks are organized in an adaptive optimal-control algorithm to synthesize an optimal strategy for energy management. The obtained optimal strategy was verified in an electric vehicle powered by combining a fuel-cell system and an ultracapacitor bank. Driving-cycle tests were conducted to investigate the fuel consumption, fuel-cell peak power, and instantaneous rate of change in fuel-cell power. The results show that the energy efficiency of the electric vehicle is significantly improved relative to that without using the optimal strategy.     

Experimental investigation on thermal performance of silica cooling plate‐aluminate thermal plate‐coupled forced convection‐based pouch battery thermal management system

The power battery as an indispensable part of electric vehicle has attracted much attention in recent years. Among these, the lithium‐ion battery is the most important option due to the high energy density, good stability, and low discharge rate. However, the thermal safety problem of lithium‐ion battery cannot be ignored. Therefore, it is very necessary to explore an effective thermal management system for battery module. Here, a thermal silica cooling plate‐aluminate thermal plate (SCP‐ATP) coupling with forced convection air cooling system as a thermal management system is proposed for improving the cooling performance of pouch battery module. The results reveal that the heat dissipating performance and temperature uniformity of pouch battery module with SCP‐ATP are greatly improved compared with other thermal management systems. Moreover, the highest temperature can be controlled below 50°C, and the temperature differences can be maintained with 3°C when the SCP‐ATP coupling forced convection is utilized to enhance the heat transfer coefficient. Furthermore, considering the cooling effectiveness and consumption cost comprehensively, the optimal air velocity of the SCP‐ATP coupling forced convection cooling system is 9 m/s. In addition, the SCP‐ATP filling with different proportions of acetone has also been investigated for pouch battery module, indicating that 50% acetone exhibited a better heat transfer effect than the 30% one. Therefore, this research would provide a significant value in the design and optimization of thermal management systems for battery module.     

Development of fuel-cell-powered electric bicycle

The design, fabrication, and testing of a prototype of electric bicycle powered by a proton exchange membrane fuel cell (PEMFC) is reported. The fuel-cell system is composed of a 300-W fuel-cell stack, metal hydride canisters, air pumps, solenoid valves, cooling fans, pressure and temperature sensors, and a microcontroller. To reduce cost, all components are commercially available except for the microcontroller, which has been developed to operate the system effectively. The fuel-cell system is installed on a commercial electric bicycle. Results show that the efficiency of the fuel-cell system can reach up to 35%, and the ratio of travel distance to fuel consumption of the prototype electric bicycle is about 1.35 km g⁻¹ H₂.     

Energy management of fuel cell/battery/supercapacitor hybrid power source for vehicle applications

This paper proposes a perfect energy source supplied by a polymer electrolyte membrane fuel cell (PEMFC) as a main power source and storage devices: battery and supercapacitor, for modern distributed generation system, particularly for future fuel cell vehicle applications. The energy in hybrid system is balanced by the dc bus voltage regulation. A supercapacitor module, as a high dynamic and high power density device, functions for supplying energy to regulate a dc bus voltage. A battery module, as a high energy density device, operates for supplying energy to a supercapacitor bank to keep it charged. A FC, as a slowest dynamic source in this system, functions to supply energy to a battery bank in order to keep it charged. Therefore, there are three voltage control loops: dc bus voltage regulated by a supercapacitor bank, supercapacitor voltage regulated by a battery bank, and battery voltage regulated by a FC. To authenticate the proposed control algorithm, a hardware system in our laboratory is realized by analog circuits and numerical calculation by dSPACE. Experimental results with small-scale devices (a PEMFC: 500-W, 50-A; a battery bank: 68-Ah, 24-V; and a supercapacitor bank: 292-F, 30-V, 500-A) corroborate the excellent control principle during motor drive cycle.     

Eco-green portable wireless power charger design with low-voltage,high-current fuel cell power source features

Since portable wireless power charger devices have grown rapidly in the market, this device has potential to become standard power charger for portable electronic devices. It offers enhanced consumer convenience and experience. This article presents an innovative portable wireless power charger that is more environmental-friendly because it uses a hydrogen gas fuel cell as the power source. Compared with fossil energy, the fuel cell is clean and renewable, which does not contribute a negative impact on the environment. A wireless power transmission (WPT) system was developed based on the electromagnetic induction technique in order to propagate electromagnetic energy from the transmitter to the receiver with operating frequency at 110 kHz. A four-cell proton exchange membrane fuel cell (PEMFC) planar module with open type at cathode side was applied to provide 4.11 W with its low-voltage and high-current features. A single-cell PEMFC produces output voltage ranging from 0.6 to 0.7 V and configures in serial to form a four-cell PEMFC planar module. Two DC-DC boost converter module in a parallel configuration was used to convert to a suitable voltage and current to the WPT module. The experimental validation shows that the developed system provides power around 1.6 W to the device battery under recharging with power efficiency delivery up to 70%. The charging experiment reveals the device battery capacity under recharging (cell phone) increases 1% in 3.3 minutes and it consumes the hydrogen at around 1.2 L.     

Design of an energy management technique for high endurance unmanned aerial vehicles powered by fuel and solar cell systems

A hybrid electric propulsion system with a power switching technique is tested in flights of long endurance unmanned aerial vehicle, interchanging power supply between fuel and solar cell systems. A fuel cell system consists of a sodium borohydride-based hydrogen generator, a 300 W scale proton-exchange membrane fuel-cell stack that is connected with a battery and a customized controller. The solar cell system consists of a maximum power point track device, a battery and 80 W solar arrays on each wing. These two power sources are controlled by a power switching technique using solid-state relays, which selectively permit either one of the two power sources, or both, to meet the load variation during flight. Using this method, both power sources are independently operated to deliver necessary power to satisfy the load demand, which means that it can extend flight endurance by alternating between solar and fuel cells with high-system reliability. The flight test is conducted over a period of 1.5 h to evaluate the designed hybrid power system by switching from fuel cell power to solar cell power, and vice versa, thereby proving system reliability as well as extending the operational time for flight.     

Two new control strategies: For hydrogen fuel saving and extend the life cycle in the hydrogen fuel cell vehicles

With the acceleration of the development process of hydrogen fuel cell electric vehicles (HFCEV), it has become very important to maximize the energy stored in the vehicle and to use the vehicle with high efficiency. This paper puts forward how to cooperate with a proton exchange membrane fuel cell (PEMFC) as the primary energy source, a lithium-ion battery (LiB) and a supercapacitor (SCAP) as the energy storage technology. Furthermore, this paper examines the effect of two new control strategies developed for HFCEV in different road models on the vehicle fuel economy and life cycle of the system components. Both control strategies applied to the system can be easily applied to the different HFCEVs with minor changes due to the simplicity of their structure and parameters. The simulation results of the study have indicated that the impact of control strategies created in different road conditions on the power of energy sources, the life cycle of system components, system efficiency and fuel economy parameters of HFCEV.     

Thermal management system of lithium‐ion battery module based on micro heat pipe array

Temperature affects the performance of electric vehicle battery. To solve this problem, micro heat pipe arrays are utilized in a thermal management system that cools and heats battery modules. In the present study, the heat generation of a battery module during a charge‐discharge cycle under a constant current of 36 A (2C) was computed. Then, the cooling area of the condenser was calculated and experimentally validated. At rates of 1C and 2C, the thermal management system effectively reduced the temperature of the module to less than 40°C, and the temperature difference was controlled less than 5°C between battery surfaces of the module. A heating plate with 30‐W power effectively improved charge performance at low temperature within a short heating time and with uniform temperature distribution. Charge capacity obviously increased after heating when battery temperature was below 0°C. This study presents a new way to enhance the stability and safety of a battery module during the continuous charge‐discharge cycle at high temperatures and low temperatures accordingly.     

Dynamic behaviour of Li batteries in hydrogen fuel cell power trains

A Li ion polymer battery pack for road vehicles (48 V, 20 Ah) was tested by charging/discharging tests at different current values, in order to evaluate its performance in comparison with a conventional Pb acid battery pack. The comparative analysis was also performed integrating the two storage systems in a hydrogen fuel cell power train for moped applications. The propulsion system comprised a fuel cell generator based on a 2.5 kW polymeric electrolyte membrane (PEM) stack, fuelled with compressed hydrogen, an electric drive of 1.8 kW as nominal power, of the same typology of that installed on commercial electric scooters (brushless electric machine and controlled bidirectional inverter). The power train was characterized making use of a test bench able to simulate the vehicle behaviour and road characteristics on driving cycles with different acceleration/deceleration rates and lengths. The power flows between fuel cell system, electric energy storage system and electric drive during the different cycles were analyzed, evidencing the effect of high battery currents on the vehicle driving range. The use of Li batteries in the fuel cell power train, adopting a range extender configuration, determined a hydrogen consumption lower than the correspondent Pb battery/fuel cell hybrid vehicle, with a major flexibility in the power management.