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Research On Key Technologies Of High Efficiency On-board Charger

Posted on:2018-12-29Degree:MasterType:Thesis
Country:ChinaCandidate:L K FengFull Text:PDF
GTID:2392330599462478Subject:Electrical engineering
Abstract/Summary:PDF Full Text Request
With the deterioration of environmental pollution and the increasing of energy crisis,new energy electric vehicles as one of the effective means of energy conservation and emission reduction have attracted more attention to many countries.The development of electric vehicles is mainly faced with the problem that domestic charging stations are not widely popularized,the continuous travel distance is too short and the charging time is too long.Charger unit as the core of battery charging for electric vehicles plays a significant role.Research on high efficiency,high reliability on-board charger can not only improve the battery charging speed,but also extend the service life of the battery.Therefore,the development of on-board charger has important practical significance for the development of electric vehicles.First,the two-level topology is selected after the advantages and disadvantages of single-stage topology and two-stage topology of on-board charger are compared and analyzed.The Boost active power factor correction topology is adopted in the front section of the AC/DC to reduce the harmonic content of the input current and improve the power factor of the converter.Be compared and analyzed of transform circuit performance and the power factor correction effect in the AC/DC control strategy respectively with average current control and one cycle control.The dynamic response of Boost APFC converter with one cycle control is analyzed and simulated in different aspects,and the shortcomings of slow dynamic response to load had be founded.To solve this problem,the current feedforward control is applied.However,the secondary ripple issues have appeared with the current forward brought,so added the notch filter in the current feedforward control is proposed to reduce the secondary ripple.Simulation results show that the dynamic response of converter to load is fast and the content of the secondary ripple is reduced greatly which has verified the feasibility of the current feed-forward control with notch filter.The secondary side in DC/DC of resonant phase shifted full bridge converter is determined to realize the soft switching of switch,reduce switch loss,improve the efficiency of the converter and eliminate the parasitic oscillation transformer in secondary side of rectifier diode.The influence brought to the series resonant to soft switch is eliminated and the reliability of the converter is improved because the original soft switching part and the resonant part which located on the second side of transformer are separated.Simulation results show that not only the soft switching of switch is achieved,but also turn-off at zero current switching in second side of rectifier diodes is realized based on full-bridge converter with resonance in second side.What's more,the simulation results have verified the correctness of the theory and provided a theory for the design of on-board charger prototype.
Keywords/Search Tags:On-board charger, Single cycle control, Power factor correction, sub side resonance, Parasitic oscillation
PDF Full Text Request
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