| Battery has been widely used in social production and people’s live, especiallyas energy storage and backup power.Lead-acid battery is the most widely usedbattery. The effect of the inconsistency, charge and discharge systems, workingenvironment of the battery makes the battery life in actual use less than the designrequirements. Equalizing charge management of the battery which is the focus ofthis study can solve the above problem.Based on working principle and characteristics of lead-acid batteries, thecircuit models of lead-acid battery and methods of SOC estimation have beendiscussed and analyzed. Analyzing and constrasting with the common balancecharging circuit topology, a dynamic and non-destructive balanced charging schemehas been used. Series battery pack which consists of three lead-acid batteries hasequalized charge.The designed modules make up with the control of the chargingcurrent, the detection of terminal voltage, charging current, and temperature of thebattery circuit. Balanced control strategy by changing the PWM duty cycle, controlthe bypass switch MOSFET on and off time and charging current of the battery,thus achieving the equilibrium charge of the lead-acid batteries. The experimentaldata show that the balanced charging scheme has high efficiency, small energyloss,fast balanced rate and high application value.Based on improved Randles model of the lead-acid battery, balanced chargingof the battery pack which consists of three lead-acid batteries has been madesimulation. Voltage and current waveforms of the charging process show therationality and effectiveness of the equalization charge module circuit. |
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