[关键词]
[摘要]
双向隔离型DC-DC变换器在超级电容储能供电的电动汽车上应用广泛,为了实现变换器中所有开关管零电压开关(ZVS)过程,提高双向隔离型变换器效率,提出了一种新型双向有源桥式变换器控制策略。在桥式变换器中增加并联谐振电感,利用占空比补偿的方法对驱动信号进行补偿,对谐振腔的电流值进行设计求解,选取合适的谐振电感值,对谐振过程中桥式结构一次侧和二次侧电压的相位差进行控制,通过脉宽调制(PWM)处理器综合调制后控制双向隔离型变换器。保证了能量双向流动的同时,实现了双向隔离型DC-DC变换器中所有开关管ZVS过程。试验测试表明,所提出的新型控制策略能够有效提高双向隔离型DC-DC变换器的效率。
[Key word]
[Abstract]
Bi-directionally isolated DC-DC converter is widely used in electric vehicles powered by super capacitor energy storage. To realize zero voltage switching (ZVS) process of all switches in converter and improve efficiency of bi-directionally isolated DC-DC converter, a new control strategy of bi-directional active bridge converter is proposed. A parallel resonant inductor is added in the bridge converter. The drive signal is compensated by the method of duty cycle compensation. The current value of resonant cavity is solved. Appropriate resonant inductor value is selected to control the phase difference between primary side and secondary side voltage of the bridge structure during resonance process. The bi-directionally isolated converter is controlled by pulse width modulation(PWM) processor after comprehensive modulation. ZVS process of all switches in bi-directionally isolated DC-DC converter is realized. Experimental results show that the new control strategy can effectively improve efficiency of bi-directionally isolated DC-DC converter.
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