三端口DC/DC变换器预测电流移相控制

针对微电网储能系统中三端口DC/DC变换器,研究了基于半开关周期采样和全开关周期采样的预测电流移相控制。分析了变换器的工作状态和开关模态,采用Y-△等效变换得到电感电流斜率,在每个开关周期驱动信号的中点时刻采样电感电流,计算不同阶段变换器的电感电流增量。基于电流采样值和电流参考值预测变换器下一个开关周期上升沿和下降沿移相比,更新该移相比使电感电流达到参考值。然后分析了两种采样模式下电感电流中直流分量消除机理,并给出三端口DC/DC变换器闭环控制策略。仿真结果验证了该控制方法的有效性,较好地解决了三端口DC/DC变换器直流偏置问题,提高了系统的动态响应和鲁棒性能。

Predictive current phase shift control of three-port DC/DC converter

For the three-port DC/DC converter in the microgrid energy storage system, the predictive current phase shift control based on half switching cycle sampling and full switching cycle sampling is studied. The working state and switching mode of the converter are analyzed. The slope of the inductor current is obtained by Y-D equivalent transformation. The inductor current is sampled at the midpoint of the driving signal of each switching cycle, and the inductor current increment of the converter at different stages is calculated. Based on the current sampling value and the current reference value, the phase shift ratios of rising edge and falling edge for the next switching cycle of the converter are predicted. By updating the phase shift ratios, the inductor current can reach the reference value. Then the elimination mechanism of DC component in the inductor current in two sampling modes is analyzed, and the closed-loop control strategy of three-port DC/DC converter is given. The simulation results verify the effectiveness of the proposed control method and solve the DC bias problem of the three-port DC/DC converter, which improves the dynamic response and robust performance of the system. This work is supported by National Key Research and Development Program of China (No. 2017YFB0903100) Science and Technology Project of State Grid Corporation of China (No. 521104170043).