Liang-Rui Chen

Bio: Liang-Rui Chen is an academic researcher from National Changhua University of Education. The author has contributed to research in topics: Battery (electricity) & Trickle charging. The author has an hindex of 16, co-authored 72 publications receiving 1761 citations. Previous affiliations of Liang-Rui Chen include National Taiwan University of Science and Technology & National Formosa University.

Sinusoidal-Ripple-Current Charging Strategy and Optimal Charging Frequency Study for Li-Ion Batteries

Abstract: In this paper, the sinusoidal-ripple-current (SRC) charging strategy for a Li-ion battery is proposed. The ac-impedance analysis is used to explore the optimal charging frequency. Experiments indicate that the optimal charging performance can be achieved by the proposed SRC with the minimum-ac-impedance frequency fZmin. Compared with the conventional constant-current constant-voltage charging strategy, the charging time, the charging efficiency, the maximum rising temperature, and the lifetime of the Li-ion battery are improved by about 17%, 1.9%, 45.8%, and 16.1%, respectively.

Design of Duty-Varied Voltage Pulse Charger for Improving Li-Ion Battery-Charging Response

Abstract: In this paper, a duty-varied voltage pulse-charge strategy (DVVPCS), that can detect and dynamically track the suitable duty of the charge pulse, is proposed to improve the battery-charge performance. To assess the system performance, a prototype of the duty-varied voltage pulse charger (DVVPC) is designed and implemented. Comparing with the standard constant-current and constant-voltage (CC-CV) charge strategy, the charge speed of the proposed DVVPCS is improved by about 14%, while the proposed DVVPCS is improved by about 5% in comparison with the conventional duty-fixed voltage pulse-charge strategy (DFVPCS). The charge efficiency of the proposed DVVPC has been improved by about 3.4% as compared with that of the general CC-CV. In comparison with conventional DFVPCS with D = 50%, the charge efficiency of the proposed DVVPCS is improved by about 1.5%. The results indicate that the DVVPCS can actually provide pulse with suitable duty to charge the battery, and the charge performance is improved.

A Design of an Optimal Battery Pulse Charge System by Frequency-Varied Technique

Abstract: In this paper, a variable frequency pulse charge system (VFPCS), that can detect and dynamically track the optimal charge frequency, is proposed to improve the battery-charge response. To assess the system performance, a prototype of the VFPCS for 600-mAh lithium-ion battery is designed and implemented. Compared with the standard constant-current and constant-voltage charge system, the charge speed of the proposed VFPCS is improved above 24%, while the proposed VFPCS is improved above 10% compared with the conventional fixed-frequency pulse charge system. The results indicate that the VFPCS can actually provide pulse with optimal frequency to charge the battery and the charge response is improved

Fuzzy-controlled Li-ion battery charge system with active state-of-charge controller

Abstract: A fuzzy-controlled active state-of-charge controller (FC-ASCC) for improving the charging behavior of a lithium-ion (Li-ion) battery is proposed. The proposed FC-ASCC is designed to replace the general constant-voltage charging mode by two kinds of modes: sense and charge. A fuzzy-controlled algorithm is built with the predicted charger performance to program the charging trajectory faster and to keep the charge operation in a proposed safe-charge area (SCA). A modeling work is conducted for analyzing and describing the Li-ion battery in charging process. A three-dimensional Y-mesh diagram for describing the charging trajectories of the proposed FC charger is simulated. A prototype of a Li-ion battery charger with FC-ASCC is simulated and realized to assess the predicted charging performance. Experiment shows that the charging speed of the proposed FC charger compared with the general one increases about 23% and the charger can safely work in the SCA.

A Biological Swarm Chasing Algorithm for Tracking the PV Maximum Power Point

Abstract: In this paper, a novel photovoltaic (PV) maximum power point tracking (MPPT) based on biological swarm chasing behavior is proposed to increase the MPPT performance for a module-integrated PV power system. Each PV module is viewed as a particle, and as a result, the maximum power point is viewed as the moving target. Thus, every PV module can chase the maximum power point (MPP) automatically. A 525 W prototype constructed by three parallel-connected 175 W PV modules is implemented to assess the MPPT performance. Comparing with a typical perturb and observe (P & O) MPPT method, the MPPT efficiency ?MPPT is improved about 12.19% in transient state by the proposed MPPT as theoretical prediction.

Power Electronics and Motor Drives in Electric, Hybrid Electric, and Plug-In Hybrid Electric Vehicles

Abstract: With the requirements for reducing emissions and improving fuel economy, automotive companies are developing electric, hybrid electric, and plug-in hybrid electric vehicles. Power electronics is an enabling technology for the development of these environmentally friendlier vehicles and implementing the advanced electrical architectures to meet the demands for increased electric loads. In this paper, a brief review of the current trends and future vehicle strategies and the function of power electronic subsystems are described. The requirements of power electronic components and electric motor drives for the successful development of these vehicles are also presented.

Energy Storage Systems for Automotive Applications

Abstract: The fuel efficiency and performance of novel vehicles with electric propulsion capability are largely limited by the performance of the energy storage system (ESS). This paper reviews state-of-the-art ESSs in automotive applications. Battery technology options are considered in detail, with emphasis on methods of battery monitoring, managing, protecting, and balancing. Furthermore, other ESS candidates such as ultracapacitors, flywheels and fuel cells are also discussed. Finally, hybrid power sources are considered as a method of combining two or more energy storage devices to create a superior power source.

Multilevel Inverter Topologies With Reduced Device Count: A Review

Abstract: Multilevel inverters have created a new wave of interest in industry and research. While the classical topologies have proved to be a viable alternative in a wide range of high-power medium-voltage applications, there has been an active interest in the evolution of newer topologies. Reduction in overall part count as compared to the classical topologies has been an important objective in the recently introduced topologies. In this paper, some of the recently proposed multilevel inverter topologies with reduced power switch count are reviewed and analyzed. The paper will serve as an introduction and an update to these topologies, both in terms of the qualitative and quantitative parameters. Also, it takes into account the challenges which arise when an attempt is made to reduce the device count. Based on a detailed comparison of these topologies as presented in this paper, appropriate multilevel solution can be arrived at for a given application.

Control Strategy for Flexible Microgrid Based on Parallel Line-Interactive UPS Systems

Abstract: In this paper, the control strategy for a flexible microgrid is presented. The microgrid presented here consists of several line-interactive uninterruptible power supply (UPS) systems connected in parallel. The control technique is based on the droop method to avoid critical communications among UPS units. Thus, a flexible microgrid is obtained to operate in either grid-connected or islanded mode. A small-signal analysis is presented in order to analyze the system stability, which gives rules to design the main control parameters. Simulation and experimental results are presented, showing the feasibility of the proposed controller.