Liang-Rui Chen

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

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.

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

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 a Reflex-Based Bidirectional Converter With the Energy Recovery Function

In this paper, a reflex charging strategy with the energy recovery function for a bidirectional converter (BC) is proposed to build a novel reflex-based BC (RBC) for increasing the battery charging efficiency in an uninterruptible power supply (UPS). The proposed RBC can provide a reflex charging current profile to charge the battery to obtain a high battery charging efficiency and prolong the battery life cycle. In particular, the negative pulse energy of the reflex charging current profile in the proposed RBC is recovered to reduce the battery charging dissipation. A soft transfer method is also developed in this paper to really erase the spike current in the RBC. A 400 W prototype is designed and implemented to verify the feasibility of the proposed RBC. Compared with a typical bidirectional converter, the battery charging efficiency, the battery charging speed, and the battery thermal deterioration effect are improved by about 10%, 8.8%, and 7%, respectively, with the proposed RBC.

Improving Phase-Locked Battery Charger Speed by Using Resistance-Compensated Technique

In this paper, a resistance-compensated phase-locked battery charger (RC-PLBC) mathematical model is built, and its s-domain transfer function is also derived. The stable, safe, and nonovercharging conditions of the RC-PLBC are discussed, and many criteria are proposed. After that, a complete design procedure is presented for designing a fast and safe RC-PLBC. A prototype of RC-PLBC is designed and realized to verify the charging performance. Comparing with a typical PLBC, the charge speed of the proposed RC-PLBC is improved by 18%, and the safety is held on.

Phase-Locked Bidirectional Converter With Pulse Charge Function for 42-V/14-V Dual-Voltage PowerNet

In this paper, a phase-locked bidirectional converter (BC) (PLBC) with pulse charge function is proposed to improve the battery charge efficiency. The circuit topology of the proposed PLBC is the same as that of the current-pump phase-locked loop (CP-PLL). Using CP-PLL inherent characteristics, a pulse current with bidirectional flow can be automatically implemented. A design example for a 42-V/14-V dual-voltage PowerNet is built to assess the PLBCs performance. Compared with the conventional BC, the battery charge efficiency ηb is improved by about 2.8%. Moreover, the battery increased temperature is reduced by about 5.7 °C simultaneously.

Improvement of Li-ion Battery Discharging Performance by Pulse and Sinusoidal Current Strategies

In this paper, the ac impedance analysis is used to explore the optimal discharging frequency for a Li-ion battery. Experiments indicate that the optimal discharging frequency is at the minimum ac impedance frequency fZmin for a conventional pulse-current (PC) discharging. In addition, a sinusoidal current (SC) discharging strategy is also proposed to achieve better performances. This SC discharging strategy improves the discharging capacity, discharging efficiency, and rising temperature of the Li-ion battery by about 1.3%, 1.32%, and 41.9%, respectively, as compared with the traditional constant-current discharging.

Modeling, analyzing and designing a phase‐locked battery charger

Abstract In this paper, a linear model for describing the Li‐ion battery charging response is developed. Then a Phase‐Locked Battery Charger (PLBC) mathematical model is built, and its s‐domain transfer function is also derived. The stable, safe and fast charging conditions of the PLBC are discussed and many criteria are proposed. After that, a complete design procedure is presented for designing a fast and safe PLBC. Finally, a test example of the PLBC is designed and implemented for a 700 mAh Li‐ion battery in order to assess the performance of the presented Li‐ion battery model, PLBC mathematical model and design criteria. Experiments show that the computer simulation is close to the actual measurement. This means that the presented models of the Li‐ion battery and the PLBS are correct and can capture major electrical characteristics. Experiments also show that a stable, fast and non‐overcharging PLBC is successfully implemented as we wanted. This indicates that the presented PLBC design procedure is valid and can really help engineers design a fast and safe battery charging system.

A design of fast‐locking without overshoot frequency‐locked servo system by fuzzy control technique

Abstract In this paper, a Fuzzy Pulse Pump Controller (FPPC) is proposed to realize a Fuzzy‐Controlled Frequency‐Locked Servo system (FC‐FLS) for getting a fast locking response without overshoot. A prototype FC‐FLS is designed and built to assess the system performance. In comparison with the Frequency Pump Controller‐based FLS (FPC‐FLS) and Variable Slope Pulse Pump Controller‐based FLS (VSPPC‐FLS), the acquisition times of the FC‐FLS are improved over 40%. In particular, there is no overshoot in the FC‐FLS for any servo distance. This means that a fast‐locking FLS, without overshoot, has been successfully implemented as theoretical prediction.

ADAPTIVE FLUORESCENT LAMP START CONTROL STRATEGY FOR DIMMABLE MAGNETIC BALLAST SYSTEM

Abstract Based on the environmental concern a novel central dimming system with magnetic ballast driven lighting system, Dimmable Magnetic Ballast System (DMBS), was presented to replace the electronic ballast driven lighting system. To make the DMBS work at a wide range of input voltages for dimming, an Adaptive Fluorescent Lamp Starter (AFLS) which can provide an adaptive preheating time and constant fire voltage for different operation voltage and environmental temperature is proposed in this paper. Experimental results show that features of an adaptive preheating time, a single‐pulse ignition with constant fire voltage, and zero glow current can be achieved. Compared with conventional electronic starters, the proposed AFLS can stretch the lifetime and operating voltage range of the DMBS.

A study of phase/frequency-locked servo system by fuzzy control technique

A novel fuzzy pulse pump controller (FPPC) is proposed to achieve a fuzzy-control-based phase/frequency-locked servo system (FC-PFLS). Three sets of membership functions are constructed according to the locking performance indexes, position error, discrete time change of position error, and the output crisp value. A set of fuzzy rules is built in the fuzzy-logic controller (FLC) to process the detected position error and provide a suitable pump voltage for the motor drives. The FPPC can fuzzilly provide the motion profiles, such as acceleration, constant, and deceleration for the motor in a fast response without overshoot and with nearly zero steady-state error. The physical model and the linearized model of the presented FC-PFLS are built. A design example of realizing an X-Y mode FC-PFLS is constructed. The experiments of the FC-PFLS comparing with DPPLS and SPSCS are conducted. In comparison with the DPPLS, the acquisition times of the presented FC-PFLS for the short, middle and long distance servos are improved by 30%, 53% and 57%, respectively. For the SPSCS, the acquisition times are improved by 30%, 14%, and the same, respectively.