Research And Design Of The Intelligent Lead-acid Battery Charger

This paper proposes a method of pulse current and floating charging with thetrace of the capacity of the Lead-Acid-Battery. By detecting SOC of the battery, theacceptable maximum current can be attained. Charging with pulse current couldeffectively eliminate the phenomenon of polarization, could improve the efficiencyand qualityof charge.This paper analyzes the variation of the parameters such as R_HF,R_t,V_bat and V_EMFwith the SOC of battery on the conditions of different charging/discharging current,with these parameters referring above a prediction model of SOC has been proposed.In this paper the whole structure of charging system is designed, with constructing ofsystem's model this paper analyzes the static and dynamic performance of systemusing Bode diagram and Nyquist diagram. By regulating the system into the typicalⅠsystem and typicalⅡsystem respectively using PI controller the output ofconstant voltage and constant current is realized. On the base of analyzing theaffection of h on the rapidity and stable performance of dynamic process of thesystem in mode of the typicalⅡsystem, the Fuzzy-PI controller is proposed. Bycontrolling the h of the typicalⅡsystem using Fuzzy controller the performance ofstability and rapidity of system is guaranteed simultaneously. The technology ofsoft-switching is applied into the design of charger, this paper designs the structure ofsoft-switching, and analyzes the realization conditions of soft-switching, deduces theformulas of resonant parameters and minimum of dutycycle of the auxiliaryswitch.In this paper a design of 60 Watt three-section pulse current and floating modecharger is accomplished, the results of experiment prove the accuracy andreasonabilityof charging method proposed above.