| The intelligent charging system for lead-acid batteries of electric vehicle consists of the main charging circuit and charging control loop.First, both the basic information of battery charging technique and charging methods are analyzed. Then, we put forward a strategy of multi-section constant-current charging method with pulse current charging and fixed-charging based on the system requirements in order to realize intelligent charging which can convert the charging mode automatically, judge the charging status automatically, realize balanced charge automatically, and stop charging automatically. This method ensures that the wave of charging-current is similar to the ideal of lead-acid batteries. Besides, the pulse current charging will remove polarization and prolong the life of batteries.In order to achieve intelligent charging, we use TI DSP controller-TMS320LF2407 to control charging. The main charging circuit consists of three-phase full wave rectifier circuit, pulse width modulated power inverter, electric energy feedback circuit, etc. The inverse circuit realizes phase-shifting control with IGBT. The charging control circuits make reasonable adjustments of the charging parameters (the charge current size, charging time) based on the sampling of information feedback, so that the batteries automatically realize intelligent charging in accordance with the strategy of multi-section constant-current charging method with pulse current charging and fixed-charging. Besides, the control circuits observe the charging and protect the system by self-checking and halting charging when mistake is found. The charging control loop consists of multi-phase current feedback circuit, IGBT drive circuit, the voltage and current detecting circuit, battery temperature observation circuit, etc.Finally, the key to intelligent charge—the end-of-charge criteria is studied, the basic processes of intelligent charging procedures are expounded, and the PID control method to rapid charging is researched.
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