Management System Of Super-Capacitor With Dynamic Equalization Techniquestudy

Super capacitor is widely used in many applications such as electric vehicles and wind power generation for its high charge and discharge efficiency,long cycle life,and high power density.The rating voltage of the super capacitor is usually between 2.5V and 3V.Therefore,the super capacitor unit needs to be connected in series to obtain the voltage level suitable for the power supply.The consistent weak differences in the manufacturing process often results in voltage unbalance between series super capacitor units,which seriously affects the storage capacity of the super capacitor group and the service life of the group.The dissertation focuses on the charge-carrying super capacitor bank balance system based on the Buck-Boost topology,demonstrates the feasibility of the program and do verification experiment.The equilibrium topology and control scheme of the super capacitor group are analyzed,and a Buck-Boost balanced topology was selected to achieve voltage equalization control.Based on this,simulink was used to perform a five-circuit super capacitor group double closed-loop simulation on the proposed circuit and equalization strategy.Finally,the hardware circuit of the super capacitor equalization system was designed,including the main circuit,auxiliary circuit and signal sampling control circuit.16-bit digital signal processor dsPIC33FJ64GS606 was selected as the main control chip.The formation of charge and discharge of the inductor was used to transfer energy.The real-time acquisition capacitor voltage and inductor current signal are converted by A/D convertor and sent to DSP.A 5-way equalization algorithm was programed to determine the state of charge and discharge of the super capacitor group and control equalization control real time.The system adopts a voltage and current double closed-loop control scheme.The direction of energy transfer is controlled through the method of duty adjustment.Finally,the voltage difference of the super capacitor group tends to be consistent,and the balanced inductor current eventually approaches 0,verifying the effectiveness of proposed equalization circuit and the equalization algorithm.