Ultracapacitor Module Research Articles

A Parallel Energy-Sharing Control Strategy for Fuel Cell Hybrid Vehicle

This paper presents a parallel energy-sharing control strategy for the application of fuel cell hybrid vehicles (FCHVs). The hybrid source discussed consists of a fuel cells (FCs) generator and energy storage units (ESUs) which composed by the battery and ultracapacitor (UC) modules. A direct current (DC) bus is used to interface between the energy sources and the electric vehicles (EV) propulsion system (loads). Energy sources are connected to the DC bus using of power electronics converters. A total of six control loops are designed in the supervisory system in order to regulate the DC bus voltage, control of current flow and to monitor the state of charge (SOC) of each energy storage device at the same time. Proportional plus integral (PI) controllers are employed to regulate the output from each control loop referring to their reference signals. The proposed energy control system is simulated in MATLAB/Simulink environment. Results indicated that the proposed parallel energy-sharing control system is capable to provide a practical hybrid vehicle in respond to the vehicle traction response and avoids the FC and battery from overstressed at the same time.

Development of Hydrogen Fuel Cell Motorcycle in South East Asia

Motorcycles are the most popular vehicles for motorised individual transport in Asia. Millions of motorcycles cause the majority of traffic-based air pollution. A prototype of a clean, silent and fuel efficient hydrogen fuel cell powered Motorcycle demonstrates an alternative. With the prototype of Pios Fuel Cell Motorcycle a proof of concept is done. "Pios" Fuel Cell Motorcycle is the latest prototype of a series of hydrogen fuel cell powered vehicles. The power train of the fuel cell motorcycle consists of fuel cell system, in hybrid with lithium polymer-ion battery and ultra capacitor module. A direct-coupled permanent magnet AC motor and an overrunning clutch coupled brushless DC motor are implemented as traction motors. To analysis different drive train configurations extensive dynamometer lab test were done. A comparison of direct fuel cell drive train with various hybridisation drive trains with ultra capacitor and lithium battery were systematically tested and analysed.

Multicascoded Sources for a High-Efficiency Fuel-Cell Hybrid Power System in High-Voltage Application

This paper presents a high-efficiency multicascoded hybrid power system for high-voltage application. For a cascoded configuration, the source is serially connected to the output terminal of a converter to increase the voltage conversion gain by one. In addition, parts of the energy from the sources are supplied directly to the output load with high-efficiency features. Based on these, a three-cascoded hybrid power system integrating the fuel cell (FC), battery, and ultracapacitor module is presented. A two-loop active FC control strategy is proposed to manage the power flows of the proposed system. The whole efficiency and hybrid power flows of the multicascoded system are discussed and demonstrated under different hybrid situations. Finally, the experimental results from a prototype circuit of the FC hybrid power system show that the hybrid system can provide 200 V of output voltage, 500 W of rated power, and about 1 kW/25 min long-term overload power. In addition, the whole efficiency of the proposed hybrid power system can achieve 93.6%.

Development of integrated fuel cell hybrid power source for electric forklift

A hybrid drivetrain comprising a 16 kW polymer electrolyte membrane fuel cell system, ultracapacitor modules and a lead-acid battery was constructed and experimentally tested in a real counterweight forklift application. A scaled-down version of the hybrid system was assembled and tested in a controlled laboratory environment using a controllable resistive load. The control loops were operating in an in-house developed embedded system. The software is designed for building generic control applications, and the source code has been released as open source and made available on the internet. The hybrid drivetrain supplied the required 50 kW peak power in a typical forklift work cycle consisting of both loaded and unloaded driving, and lifting of a 2.4 tonne load. Load variations seen by the fuel cell were a fraction of the total current drawn by the forklift, with the average fuel cell power being 55% of nominal rating. A simple fuel cell hybrid model was also developed to further study the effects of energy storage dimensioning. Simulation results indicate that while a battery alone significantly reduces the load variations of the fuel cell, an ultracapacitor reduces them even further. Furthermore, a relatively small ultracapacitor is enough to achieve most of the potential benefit.

An Electric Vehicle Conversion using Batteries and Ultracapacitors

The initial findings and performance of a prototype electric vehicle conversion of a famous Malaysian city car; the perodual kancil, is presented in this paper. The 660 cc, three cylinder carbureted engine rated at 31 Hp (22.1 KW) was replaced with a 48-72 V series wound DC motor rated at 8 KW continuous and 20KW peak. The battery pack consists of eight T105 Trojan 6 V, 225 Ah deep cycle lead acid battery which builds up a voltage of 48 V. In addition to this, an ultracapacitor module (165 F, 48 V) is connected in parallel using high power contactors in order to investigate the increase in performance criteria such as acceleration, range, battery life etc which have been proven in various literatures via simulation studies. A data acquisition system is setup in order to collect real world driving data from the electric vehicle on the fly along a fixed route. Analysis of collected driving data is done using MATLAB software and comparison of performance of the electric vehicle with and without ultracapacitor module is made.

Dynamic SOC Compensation of an Ultracapacitor Module for a Hybrid Energy Storage System

The ultracapacitor module has recently been recast for use in hybrid energy storage systems (HESSs). As a result, accurate state-of-charge (SOC) estimation for an ultracapacitor module is as important as that of primary sources in order to be utilized efficiently in an energy storage system (ESS). However, while SOC estimation via the open-circuit voltage (OCV) method is generally used due to its linear characteristics compared with other ESSs, this method results in many errors in cases of highcurrent charging/discharging within a short time period. Accordingly, this paper introduces a dynamic SOC estimation algorithm that is capable of SOC compensation of an ultracapacitor module even when there is a current input and output. A cycle profile that simulates the operating conditions of a mild-HEV was applied to a vehicle simulator to verify the effectiveness of the proposed algorithm.

Characterization, Analysis and Modeling of an Ultracapacitor

Ultracapacitors are potentially promising power-augmentation devices in hybrid powertrains. A commercial ultracapacitor module was characterized under standard procedures to assess its performance. Tests were carried out on a platform, with which ambient temperature can be regulated and charge/discharge procedures can be implemented. Key parameters of the ultracapacitor module obtained from tests were used to develop a control-oriented ultracapacitor model proposed in the paper. Simulation results of this model in a stable discharge procedure and in dynamic procedures (i.e. driving cycles) showed excellent agreement with results obtained from experiments, indicating that the ultracapacitor model is accurate enough to be used in further electric powertrain control simulation.

Analysis, Design, and Control of Bidirectional Cascoded Configuration for a Fuel Cell Hybrid Power System

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This paper presents a cascoded configuration combining a fuel cell (FC), a battery, and an ultracapacitor module (UCM) to create a hybrid power system. A cascoded configuration is constructed using a modified bidirectional flyback converter, which connects the battery and UCM in cascode to efficiently provide hybrid power. An active FC voltage control strategy is presented to manage the power flows of the proposed cascoded system. In this paper, the simulated hybrid power of the motion of an electric vehicle is illustrated in different situations. The experimental results show that the power flows using the proposed control strategy verify the theoretical analysis. In addition, the overall efficiency of the proposed hybrid power system at overload operation is much higher than the conventional one, and it can achieve 96%. </para>

Predictive Control of Voltage and Current in a Fuel Cell–Ultracapacitor Hybrid

This paper presents a system integration and control strategy for managing power transients on a Nexa polymer electrolyte membrane fuel cell (FC) with the assistance of an ultracapacitor (UC) module. The two degrees of freedom provided by the use of two dc/dc converters enable the independent low-level control of dc bus voltage and the current split between the FC and UC. The supervisory-level control objectives are to respond to rapid variations in load while minimizing damaging fluctuations in FC current and maintaining the UC charge (or voltage) within allowable bounds. The use of a model predictive control approach which optimally balances the distribution of power between the FC and UC while satisfying the constraints is shown to be an effective method for meeting the supervisory-level objectives. The results are confirmed in experiments.

Development of ultracapacitor modules for 42-V automotive electrical systems

Two types of ultracapacitor modules have been developed for use as energy-storage devices for 42-V systems in automobiles. The modules show high performance and good reliability in terms of discharge and recharge capability, long-term endurance, and high energy and power. During a 42-V system simulation test of 6-kW power boosting/regenerative braking, the modules demonstrate very good performance. In high-power applications such as 42-V and hybrid vehicle systems, ultracapacitors have many merits compared with batteries, especially with respect to specific power at high rate, thermal stability, charge–discharge efficiency, and cycle-life. Ultracapacitors are also very safe, reliable and environmentally friendly. The cost of ultracapacitors is still high compared with batteries because of the low production scale, but is decreasing very rapidly. It is estimated that the cost of ultracapacitors will decrease to US$ 300 per 42-V module in the near future. Also, the maintenance cost of the ultracapacitor is nearly zero because of its high cycle-life. Therefore, the combined cost of the capacitor and maintenance will be lower than that of batteries in the near future. Overall, comparing performance, price and other parameters of ultracapacitors with batteries, ultracapacitors are the most likely candidate for energy-storage in 42-V systems.