Fuel cell/battery passive hybrid power source for electric powertrains

The concept of passive hybrid, i.e. the direct electrical coupling between a fuel cell system and a battery without using a power converter, is presented as a feasible solution for powertrain applications. As there are no DC/DC converters, the passive hybrid is a cheap and simple solution and the power losses in the electronic hardware are eliminated. In such a powertrain topology where the two devices always have the same voltage, the active power sharing between the two energy sources can not be done in the conventional way. As an alternative, control of the fuel cell power by adjusting its operating pressure is elaborated. Only pure H₂/O₂ fuel cell systems are considered in this approach. Simulation and hardware in the loop (HIL) results for the powertrain show that this hybrid power source is able to satisfy the power demand of an electric vehicle while sustaining the battery state of charge.     

Transient power characteristic measurement of a proton exchange membrane fuel cell generator

An experimental study on the transient power characteristics of a fuel cell generator has been conducted. The generator is hybridized by a proton exchange membrane (PEM) as the main power source and a lithium-ion battery as the secondary power source. power-conditioning module consisting of a main bidirectional converter and an auxiliary converter has been designed to manage the hybrid power of the generator that copes with fast dynamics of variable loads. Sensors embedded in the generator have measured the electrical properties dynamically. It was found that the present power-conditioning scheme has well controlled the power flow between the fuel cell stack and the battery by regulating the power flow from or to the battery. In addition, the thermal management system using pulse width modulation (PWM) schemes could limit the operation temperature of the fuel cell generator in a designed range. Furthermore, the dynamics of electrical efficiency of the generator are found to be parallel with those of the net system power. Finally, the stability and reliability of the fuel cell generator is proven by the rational dynamic behaviors of thermal and electrical properties for over 30-h demonstration.     

Optimized power management based on adaptive-PMP algorithm for a stationary PEM fuel cell/battery hybrid system

This research develops an efficient and robust polymer electrolyte membrane (PEM) fuel cell/battery hybrid operating system. The entire system possesses its own rapid dynamic response benefited from hybrid connection and power split characteristics due to DC/DC buck-boost converter. An indispensable energy management system (EMS) plays a significant role in achieving optimal fuel economy and in a promising running stability. EMS as an indispensable part plays a significant role in achieving optimal fuel economy and promising operation stability. This study aims to develop an adaptive supervisory EMS that comprises computer-aided engineering tools to monitor, control, and optimize the performance of the hybrid power system. A stationary fuel cell/battery hybrid operating system is optimized using adaptive-Pontryagin's minimum principle (A-PMP). The proposed algorithm depends on the adaptation of the control parameter (i.e., fuel cell output power) from the state of charge (SOC) and load power feedback. The integrated model simulated in a Matlab/Simulink environment includes the fuel cell, battery, DC/DC converter, and power requirements models by analyzing the three different load profiles. Real-time experiments are performed to verify the effectiveness of EMS after analyzing the simulated operating principle and control scheme.     

The study on the power management system in a fuel cell hybrid vehicle

This paper presents a model of a hybrid electric vehicle, based on a primary proton exchange membrane fuel cell (PEMFC) and an auxiliary Li-ion battery, and its dynamics and overall performance. The power voltage from the fuel cell is regulated by a DC/DC converter before integrating with the Li-ion battery, which provides energy to the drive motor. The driving force for propelling the wheels comes from a permanent magnet synchronous motor (PMSM); where the power passes through the transmission, shaft, and the differential.     

Experimental investigation on the online fuzzy energy management of hybrid fuel cell/battery power system for UAVs

The hybrid powerplant combining a fuel cell and a battery has become one of the most promising alternative power systems for electric unmanned aerial vehicles (UAVs). To enhance the fuel efficiency and battery service life, highly effective and robust online energy management strategies are needed in real applications.In this work, an energy management system is designed to control the hybrid fuel cell and battery power system for electric UAVs. To reduce the weight, only one programmable direct-current to direct-current (dcdc) converter is used as the critical power split component to implement the power management strategy. The output voltage and current of the dcdc is controlled by an independent energy management controller. An executable process of online fuzzy energy management strategy is proposed and established. According to the demand power and battery state of charge, the online fuzzy energy management strategy produces the current command for the dcdc to directly control the output current of the fuel cell and to indirectly control the charge/discharge current of the battery based on the power balance principle.Another two online strategies, the passive control strategy and the state machine strategy, are also employed to compare with the proposed online fuzzy strategy in terms of the battery management and fuel efficiency. To evaluate and compare the feasibility of the online energy management strategies in application, experiments with three types of missions are carried out using the hybrid power system test-bench, which consists of a commercial fuel cell EOS600, a Lipo battery, a programmable dcdc converter, an energy management controller, and an electric load. The experimental investigation shows that the proposed online fuzzy strategy prefers to use the most power from the battery and consumes the least amount of hydrogen fuel compared with the other two online energy management strategies.     

Time delay control for fuel cells with bidirectional DC/DC converter and battery

Transient behavior is a key property in the vehicular application of proton exchange membrane (PEM) fuel cells. A better control technology is constructed to increase the transient performance of PEM fuel cells. A steady-state isothermal analytical fuel cell model is constructed to analyze mass transfer and water transport in the membrane. To prevent the starvation of air in the PEM fuel cell, time delay control is used to regulate the optimum stoichiometric amount of oxygen, although dynamic fluctuations exist in the PEM fuel cell power. A bidirectional DC/DC converter connects the battery to the DC link to manage the power distribution between the fuel cell and the battery. Dynamic evolution control (DEC) allows for adequate pulse-width modulation (PWM) control of the bidirectional DC/DC converter with fast response. Matlab/Simulink/Simpower simulation is performed to validate the proposed methodology, increase the transient performance of the PEM fuel cell system and satisfy the requirement of energy management.     

Maximum power point tracking of a proton exchange membrane fuel cell system using PSO-PID controller

Fuel cells output power depends on the operating conditions, including cell temperature, oxygen partial pressure, hydrogen partial pressure, and membrane water content. In each particular condition, there is only one unique operating point for a fuel cell system with the maximum output. Thus, a maximum power point tracking (MPPT) controller is needed to increase the efficiency of the fuel cell systems. In this paper an efficient method based on the particle swarm optimization (PSO) and PID controller (PSO-PID) is proposed for MPPT of the proton exchange membrane (PEM) fuel cells. The closed loop system includes the PEM fuel cell, boost converter, battery and PSO-PID controller. PSO-PID controller adjusts the operating point of the PEM fuel cell to the maximum power by tuning of the boost converter duty cycle. To demonstrate the performance of the proposed algorithm, simulation results are compared with perturb and observe (P&O) and sliding mode (SM) algorithms under different operating conditions. PSO algorithm with fast convergence, high accuracy and very low power fluctuations tracks the maximum power point of the fuel cell system.     

A new application of the UltraBattery to hybrid fuel cell vehicles

This study involves investigation of fuel cell hybrid vehicles. The main power source in the dynamic configuration is a proton exchange membrane fuel cell. An energy performance comparison is conducted between the use of a lithium‐ion battery (Automotive Energy Supply Corporation, Japan) and the UltraBattery (Furukawa Battery Company, Japan) as auxiliary power sources. The MATLAB/Simulink for simulation is used to observe dynamic behavior and overall performance. This study describes the simulation frameworks of the proton exchange membrane fuel cell, ultracapacitor, lead–acid battery, and UltraBattery. Then, the Economic Commission for Europe 40 driving cycle is used to test and investigate the performance of the fuel cell hybrid vehicle. Four energy output models are adopted to simulate the energy demand and the energy motor output of the dual power source, namely the high‐load demand, general demand, low‐load demand, and charge models. The simulation results indicate that the lithium battery recycles 0.1% more work compared with the UltraBattery. Regarding fuel economy, the UltraBattery is only 0.1% inferior to the lithium battery. The expected cost of an UltraBattery with the same specifications is 35% less than that of a lithium battery. Considering fuel economy and cost simultaneously, the UltraBattery can compete with the lithium battery. Copyright © 2015 John Wiley & Sons, Ltd.     

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.     

Modeling and control of a portable proton exchange membrane fuel cell-battery power system

A portable proton exchange membrane (PEM) fuel cell-battery power system that uses hydrogen as fuel has a higher power density than conventional batteries, and it is one of the most promising environmentally friendly small-scale alternative energy sources. A general methodology of modeling, control and building of a proton exchange membrane fuel cell-battery system is introduced in this study. A set of fuel cell-battery power system models have been developed and implemented in the Simulink environment. This model is able to address the dynamic behaviors of a PEM fuel cell stack, a boost DC/DC converter and a lithium-ion battery. To control the power system and thus achieve proper performance, a set of system controllers, including a PEM fuel cell reactant supply controller and a power management controller, were developed based on the system model. A physical 100 W PEM fuel cell-battery power system with an embedded micro controller was built to validate the simulation results and to demonstrate this new environmentally friendly power source. Experimental results demonstrated that the 100 W PEM fuel cell-battery power system operated automatically with the varying load conditions as a stable power supply. The experimental results followed the basic trend of the simulation results.     

A novel PEMFC power conditioning system based on the interleaved high gain boost converter

Power converter units are crucial components in proton exchange membrane fuel cell (PEMFC) energy generation systems. For this reason, and also motivated by the demands in high quality power conditioning for PEMFC systems, we propose the application of an interleaved high gain boost converter topology with a diode clamped multilevel inverter as power interface. The main advantages of the proposed scheme encompass: high voltage conversion ratio, input current ripple mitigation, and voltage balancing across output capacitors. These characteristics make this converter ideal for grid-connection purposes, acting as an interface for renewable energy sources that provide low voltages and demand low current ripples. The underlying theoretical analysis as well as simulation and experimental validation are presented in this paper.     

An actively controlled fuel cell/battery hybrid to meet pulsed power demands

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 portable 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 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 35 W hydrogen-fueled polymer electrolyte membrane fuel cell and a lithium-ion battery pack of six cells yielded a peak power of 100 W, 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 investigated 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 135 W, about four times that of the fuel cell alone. Finally, three power sources including 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.     

Test of a PEM fuel cell with low voltage static converter

This paper presents a test of a 500 W polymer electrolyte membrane (PEM) fuel cell connected with a power electronic converter. The aim of this device is to develop fuel cell dynamic models and to study converter structure and control to adapt fuel cell to an electrical power train. The design of the converter is first discussed before presenting different experimental results involving thermodynamic and mechanical phenomena of the PEM fuel cell.     

Experimental investigation on the dynamic performance of a hybrid PEM fuel cell/battery system for lightweight electric vehicle application

A hybrid system combining a 2 kW air-blowing proton exchange membrane fuel cell (PEMFC) stack and a lead–acid battery pack is developed for a lightweight cruising vehicle. The dynamic performances of this PEMFC system with and without the assistance of the batteries are systematically investigated in a series of laboratory and road tests. The stack current and voltage have timely dynamic responses to the load variations. Particularly, the current overshoot and voltage undershoot both happen during the step-up load tests. These phenomena are closely related to the charge double-layer effect and the mass transfer mechanisms such as the water and gas transport and distribution in the fuel cell. When the external load is beyond the range of the fuel cell system, the battery immediately participates in power output with a higher transient discharging current especially in the accelerating and climbing processes. The DC–DC converter exhibits a satisfying performance in adaptive modulation. It helps rectify the voltage output in a rigid manner and prevent the fuel cell system from being overloaded. The dynamic responses of other operating parameters such as the anodic operating pressure and the inlet and outlet temperatures are also investigated. The results show that such a hybrid system is able to dynamically satisfy the vehicular power demand.     

A suitable model plant for control of the set fuel cell−DC/DC converter

In this work a state and transfer function model of the set made up of a proton exchange membrane (PEM) fuel cell and a DC/DC converter is developed. The set is modelled as a plant controlled by the converter duty cycle. In addition to allow setting the plant operating point at any point of its characteristic curve (two interesting points are maximum efficiency and maximum power points), this approach also allows the connection of the fuel cell to other energy generation and storage devices, given that, as they all usually share a single DC bus, a thorough control of the interconnected devices is required. First, the state and transfer function models of the fuel cell and the converter are obtained. Then, both models are related in order to achieve the fuel cell+DC/DC converter set (plant) model. The results of the theoretical developments are validated by simulation on a real fuel cell model.     

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.     

Power management strategy for vehicular-applied hybrid fuel cell/battery power system

In this paper, a control strategy for a hybrid PEM (proton exchange membrane) fuel cell/BES (battery energy system) vehicular power system is presented. The strategy, based on fuzzy logic control, incorporates the slow dynamics of fuel cells and the state of charge (SOC) of the BES. Fuel cell output power was determined according to the driving load requirement and the SOC, using fuzzy dynamic decision-making and fuzzy self-organizing concepts. An analysis of the simulation results was conducted using Matlab/Simulink/Stateflow software in order to verify the effectiveness of the proposed control strategy. It was confirmed that the control scheme can be used to improve the operational efficiency of the hybrid power system.     

Development of a power management unit for small portable direct borohydride fuel cell–NiMH battery hybrid system

In this study, a small portable fuel cell/battery hybrid system has been developed. The system consists of a single portable direct borohydride/peroxide fuel cell (DBPFC), NiMH battery and power management unit (PMU). The battery has been used as a primary power source and has been discharged at constant load. When its state of charge is reduced, the DBPFC charges the battery and powers the load simultaneously. A DC–DC Boost converter has been used as a PMU. The DBPFC has provided the total power of 0.21 Wh into the system during the charge. During this experimental study fuel (NaBH₄) efficiency of 37% has been achieved in the hybrid system, while the system efficiency has been calculated as 34.5%.     

Three-port single-phase three-wire power converter interface for micro grid

This paper proposes a three-port single-phase three-wire (TPSPTW) power converter interface integrating an isolated current-fed full-bridge power converter (ICFPC), a three-port power converter (TPPC), a fuel cell and a battery set for micro grid (MG).The ICFPC is used to control the output power of fuel cell and to step-up its output voltage to the voltage of high-voltage DC port of the TPPC. The TPPC can manage the power conversion between the fuel cell, the battery set, the loads and the utility. This power converter interface charges the battery set, outputs AC power and acts as an active power filter (APF) in the grid-connection mode, supplies uninterruptible power to the loads when it operates in the stand-alone mode. The fuel cell outputs a programmed power regardless of whether the power converter interface operates in the grid-connection mode or in the stand-alone mode. The programmed power outputted from the fuel cell is the average power of load under the stand-alone mode. The battery set is used to respond to the varied power of loads under the stand-alone mode. A prototype is developed to verify the performance of power converter interface, and the experimental results are as expected.     

A novel self-tuning type-2 fuzzy maximum power point tracking technique for efficiency enhancement of fuel cell based battery chargers

Given the uncertainties associated with proton-exchange membrane fuel cell systems and relatively low efficiency of the fuel cell stacks for low-power applications, designing a high-efficiency maximum power point tracking (MPPT) controller for the fuel cell electric vehicles is an important and also technically challenging issue. For this purpose, in this article, aiming to develop a high-efficiency and low cost battery charger, a novel self-tuning type-2 fuzzy MPPT controller is presented. The main task of the controller is to provide the better performance and regulate the switching duty cycle of the used power converter under the system's uncertainty conditions in order to dynamically extract the maximum power from the fuel cell system and maintain the battery at its highest possible state of charge while protecting it from overcharging. For the sake of computational efficiency, an improved invasive weed optimization algorithm, called elitist invasive weed optimization (EIWO), is also presented to tune the type-2 fuzzy set parameters, whose improvement is demanding due to the limited human experience and knowledge. All data processing and simulations are conducted in the MATLAB software. Finally, the performance of the proposed MPPT controller is examined through using experimental tests with a prototype device.