| This paper focuses on the Photovoltaic charging control system.We pay our emph- ases on the implementation including selecting parameters,topology structure,control strategy,Mppt,maintenance of storage battery,and so on.The basic work principles of solar cells and lead-acid batteries have been researched.Through the simulation, the solar cells output performance has been shown. the main factors in the charging process that Shorten the life of the Lead-acid batteries have been analysed.The plan of three-state charging method is used ,which joints the charge and discharge characteristic of the accumulator together with P-V system's uniqueness. Quick-charge is carried out by MPPT(maximum power point tracing)which uses the incremental conductance algorithm,In the state of over-charge and float-charge,it uses proportion integral control method to realize constant voltage charge.According to the characteristics of the system, adopting Buck circuit as its main charge circuit,A charge controller is designed basing on the pulse width modulation technology. This system USES MSP430F235 as the main controller,the voltage of the solar and batteries are constantly detected.The Duty cycle of the switch is adjusted through the feedback of charging current or the charging voltage. The quick charge adapting MPPT,the over charge and the flate-charge are respectively achieved. This paper has presented the hardware design procedure of the photovoltaic power controller based on MSP430F235 and accomplished the relevant program and algorism using C language.Experimental results indicates that the charge controller can judge the state of battery effectively.And it also can take the corresponding charging method. The MPPT charge rapidly tracking of external conditions change,and the steady-state concussion is little,so that this charge controller can improve the utilization of solar-energy,and high in accuracy in over-charging and float-charging stages,and prolong the life of battery. |
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