Research On High-Capacity Inteligent Charging System For Lead-acid Batteries

This paper described the design of a high-capacity intelligent charging system for lead-acid batteries, including the research on charging methods and the design of the charging system.Based on the analysis of the charging theory and the investigation of many charging methods, a two-stage charging strategy was brought forward. At the former stage of charging, the fast charging method was used which is the combination of multi-section constant-current charging method with pulsant charging method. And at the latter stage, the constant-voltage charging method was adopted. The theory and the tests indicated that by application of the charge strategy, the charging efficiency was raised and the charging period was reduced.Ground on the HF SPS (High-Frequency Switching Power Supply), the charging system was designed which was composed of a three-phase rectifying cell, a phase-shifted zero-voltage-switching PWM DC/DC full-bridge cell and an energy recovery cell. In the DC/DC cell, IGBT (Isolated Gate Bipolar Transistor) was selected as the switch that was driven by EXB841 module. And the charging control system was based on TMS320LF2407 chip, which can produce controllable PWM signal with dead time. Using this construction of power supply, switching loss was much reduced and higher frequency could be gained.Based on the analysis of many charge-termination control methods, an integrated control method was adopted to judge whether batteries was full-charge or not. And an improved PID control algorithm was used to realize the constant-current charging and the constant-voltage charging.