Equalization Techniques Of Storage Batteries On EV & HEV

A new storage battery equalizing-utilization system applied on EV & HEV ispresented in this paper. The system is composed of equalization discharge unit,equalization charge unit and auxiliary equalization unit. Circuit frame, functionmechanism and control strategy of each unit are described in detail.Storage batteries' unequal problem due to charging and discharging in series will leadbatteries's life to be impaired seriously. Many techniques have been designed tohandle the unequal problem yet most of them have defects of complex structure, highcost and low efficiency.A new technique is present in this paper to eliminate the unequal state of seriesbatteries in discharging process. Multilevel synthesize equalizing discharging circuitis designed to realize dynamic discharging equalization of series batteries efficientlyby implementing corresponding control strategy. In addition, harmful harmonics inoutput voltage can be eliminated entirely and current total harmonic distortion (THD)can be restricted in low range hence to improve waveform of motor which canstabilize motor function and reduce energy consumed. Simulation results testifiedadvantages of this discharging equalization technique.To actualize equalization of series batteries in charging process, a new conceive wasapplied in equalizing charging unit. Dynamic voltage distribution charge circuitdesigned can real-time adjust the energy charged into batteries. By relevant controlstrategy to circuit the process of batteries charging can be equalized efficiently andoptimal charging current according with Mass theory can be acquired. Availablenessof dynamic voltage distribution charge technique has been proved by simulationexperiments.Switched capacitor series is adopted in auxiliary equalization unit to equalize allseries single batteries. This existing technique was appraised by math analysis andsimulation experiments in this paper detailedly. And some constructive conclusionwere educed about the practicality of switched capacitor series equalization technique.