| With the social and economic development, cars become very important inpeople’s lives. This will result the increasing number of oil and other non-renewableemerge consumption and causing serious impact on the environment.However, Electric vehicle has been one of development directions of globalautomobile industry, because its advantage of saving energy and non-polluting. Thepower of electric vehicles is from the battery pack; therefore, it is very important todevelopment the charging system to popularize electric vehicles.The main objective of this paper is to develop the high efficiency, high powerdensity Lithium-ion battery charging system. The full-bridge zero-voltage PWMconverter with diode-clamp was chosen as the main circuit of charging system. Thenthe characteristics of the main circuit were analyzed and the parameters of thecomponents were designed. Then establishing small signal model of the converterwas established.It is discussed that the changing of parameters in the battery pack model affectsthe control accuracy and dynamic response of the charging system, throughestablishing the peak current small model of the full-bridge converter and loadbattery packs’ model of the charging system. Moreover, the disadvantages of fixedparameters PID control are put forward. An online identification method ispresented for battery pack charging parameters, which is based on a relay feedbacksystem. According to the results of parameters identification, a self-tuning method ispresented to regulate controller parameters in order to make the charging systemobtain the specified crossover frequency and phase margin. As a consequence, theimpact of input voltage fluctuations of changers and characteristics change of thebattery pack in charging process is mitigated for battery pack charging systemstability and dynamic performance.Based on the above analysis, a1kW Lithium-ion battery charging system wasdeveloped; experimental test and data analysis were conducted. The experimentalresults show that the charging power supply of electric vehicle can completely meetthe requirements of efficiency. |
