输入串联输出并联的直流变换器控制策略研究

输入串联输出并联型直流变换器能降低开关管的开关应力,适用于高输入电压、大功率的直流变换场合。为了保证该变换器的可靠工作,必须确保其输入分压电容均压和输出电流均流。文中首先从能量的角度出发,分析了输入串联输出并联型直流变换器的输入均压和输出均流之间的关系,指出输出均流控制不能保证输入均压,而输入均压控制可以确保输出均流;然后提出一种新的输入均压的控制方法,在保证输入均压和输出均流的同时,该方法可以实现输入电压的均压控制与输出电压的调节相解耦,有利于分别独立设计各个输入电容电压和输出电压的闭环控制,同时交错控制下的电流纹波抵消效应使输出滤波电容得到了减小;仿真和实验结果验证了该方法的有效性。

Control Strategy for Input-Series Output-Paralleled DC-DC Converters

Input-series and output-parallelled (ISOP) converter can reduce the voltage stress of all switches, so it is very suitable for the high input voltage and high power DC-DC conversion application. In order to make the ISOP converter work normally, to ensure the voltage sharing of the input divided capacitors and current sharing of the output current of each module is very important.The relationship is analyzed between the voltage sharing and the current sharing of the input-series output-paralleled DC-DC converter in terms of the energy, and it points out that the output current sharing cannot guarantee the input voltage sharing, while the input voltage sharing is possible to guarantee the output current sharing. Then a practical control strategy for the input voltage sharing which has no influence on the output voltage is proposed, the decoupling control of the input voltage and the output voltage is derived. Thus the close-loop controls of each input capacitor voltage and the output voltage can be designed independently. At the same time, the canceling effect of the current wave reduces the filter capacitor for the interleaving control; the simulation and experimental results are presented to verify the effectiveness of the proposed method.