J. Van Mierlo

A DSP-Based Dual-Loop Peak DC-link Voltage Control Strategy of the Z-Source Inverter

This paper proposes a direct dual-loop peak dc-link voltage control strategy, with outer voltage loop and inner current loop, of the Z-source inverter (ZSI). The peak dc-link voltage is estimated by measuring both the input and capacitor voltages. With this proposed technique, a high-performance output voltage control can be achieved with an excellent transient performance including input voltage and load current variations with minimized nonminimum phase characteristics caused by the right half-plane zero in the control to peak dc-link voltage transfer function. Both controllers are designed based on a third-order small-signal model of the ZSI using the direct digital control method. The performance of the proposed control strategy is verified by simulation and experimental results of a 30-kW ZSI prototype.

Innovative iteration algorithm for a vehicle simulation program

Resulting from Ph.D. research, a vehicle simulation program is proposed and continuously developed, which allows simulation of the behavior of electric, hybrid, fuel cell, and internal combustion vehicles while driving any reference cycle. The goal of the simulation program is to study power flows in the drivetrains of vehicles and the corresponding component losses, as well as to compare different drivetrain topologies. This comparison can be realized for energy consumption and emissions, as well as for performance (acceleration, range, maximum slope, etc.). The core of this program, consisting of a unique iteration algorithm, will be highlighted in this paper. This algorithm not only allows the calculation of the limits of vehicle acceleration in the function of drivetrain component characteristics, but at the same time is able to develop and evaluate the different power-management strategies of hybrid vehicles, combining combustion engines and electric motors. Furthermore, the comprehensive iteration algorithm is demonstrated to be very efficient in handling any type of working limit for all components in different types of drivetrains, which results in an accurate and modular vehicle simulation program with high data flexibility.

An Advanced Power Electronics Interface for Electric Vehicles Applications

Power electronics interfaces play an increasingly important role in the future clean vehicle technologies. This paper proposes a novel integrated power electronics interface (IPEI) for battery electric vehicles (BEVs) in order to optimize the performance of the powertrain. The proposed IPEI is responsible for the power-flow management for each operating mode. In this paper, an IPEI is proposed and designed to realize the integration of the dc/dc converter, on-board battery charger, and dc/ac inverter together in the BEV powertrain with high performance. The proposed concept can improve the system efficiency and reliability, can reduce the current and voltage ripples, and can reduce the size of the passive and active components in the BEV drivetrains compared to other topologies. In addition, low electromagnetic interference and low stress in the power switching devices are expected. The proposed topology and its control strategy are designed and analyzed by using MATLAB/Simulink. The simulation results related to this research are presented and discussed. Finally, the proposed topology is experimentally validated with results obtained from the prototypes that have been built and integrated in our laboratory based on TMS320F2808 DSP.

Modelling and design of super capacitors as peak power unit for hybrid electric vehicles

This paper reports about the design of a peak power unit for hybrid electric vehicles and the modelling of the power control strategy to optimise the drive trains performance. A common DC bus of the hybrid drive train is defined and was provided with a peak power unit using super capacitors, connected via a bi-directional DC/DC converter. This architecture allows a fast load response and a high efficiency of the total electric drive train. An optimised control strategy is needed to ensure an optimal distribution of the power flow between the peak power unit and the main energy source.

Test Bench of Hybrid Electric Vehicle with the Super Capacitor based Energy Storage

In this paper, the research and test bench of hybrid electric vehicle has been presented, which comprises power supply system, super capacitor based energy storage, traction system and the simulated load of vehicle. In order to ensure good operating condition of main power supply and high efficiency in hybrid electric vehicle, energy sources control and management strategies were specified. They have been verified in this platform.

Using Super Capacitor Based Energy Storage to Improve Power Quality in Distributed Power Generation

Distributed power generation will be formed in many weak distribution networks, after renewable energy sources are connected to them. It is very important to increase the reliability and efficiency of using these renewable energy sources. By using DVR (dynamic voltage restorer), the power quality problem in distributed power generation (e.g. voltage fluctuation) can effectively be solved. In this paper, super capacitor based energy storage will be used as the peak power unit, to ensure the power quality on the both sides of the DVR during short time and on the one side of the DVR during long time duration. The proposed control methods of each inverter and converter have been verified in Matlab simulation and tested in our laboratory. High power quality can be achieved in distributed power generation with the presented systems

Lithium-ion capacitor — Advanced technology for rechargeable energy storage systems

This paper presents the electrical and thermal behaviour of an advanced lithium-ion capacitor (LIC) based rechargeable energy storage systems. In the proposed study, an extended statistical analysis has been performed to evaluate the main electrical parameters such as resistance, power, capacitance, rate capabilities, variation between cells and thermal parameters. Based on the performed analysis, an electrical model has been developed for dimensioning and evaluation of various applications based on lithium-ion capacitor technology.

A comparative study of different control strategies of On-Board Battery Chargers for Battery Electric Vehicles

On-Board Battery Charger is one of the key components required for the emergence and acceptance of Battery Electric Vehicles (BEVs). The control strategy of the battery charger plays an important role in the development of BEVs. Therefore, the proper selection of this control strategy can significantly improve the performance of the BEVs during charging mode from the grid. In this paper, a comparative study of different control strategies of on-board battery chargers for BEVs is presented. In this research, three control strategies are designed and applied to control the power flow of the on-board battery charger during charging mode from the ac grid. These control strategies are hysteresis current control (HCC), Proportional-Integral Control (PIC) and Proportional-Resonant Control (PRC). These control strategies are designed and analyzed by using MATLAB/Simulink. The simulation and experimental results are provided.

Lithium Iron Phosphate - Assessment of Calendar Life and Change of Battery Parameters

This paper represents the calendar life cycle test results of a 7Ah lithium iron phosphate battery cell. In the proposed article and extended analysis has been carried out for the main aging parameters during calendar life and the associated impact of the used battery model. From the analysis, it has been showed that the impact of high temperatures and state of charge is harmful for the lifetime of the battery. Therefore, there is a need for having a dedicated control strategy for keeping the battery in the most appropriate operating condition. The FreedomCar battery model parameters have been analyzed during calendar life.

Electro-Thermal Modeling of New Prismatic Lithium-Ion Capacitors

Due to increasing demand of using high energy and high power storages applicable in different applications such as hybrid electric vehicles, hybrid Lithium Ion Capacitors have been taken into account more than ever. In this paper a second order model is considered for and based on that model and HPPC (hybrid pulse power characterization) test, parameters have been identified. Then based on evaluation of internal resistance total power losses have been calculated. Regarding to the cell temperature prediction, a first order model has been considered and based on measured surface temperature and also calculated power losses, parameters of thermal model have been identified. At the end both electrical and thermal models have been merged and final model has been validated.