三电平混合全桥DC-DC变换器全局电流应力优化与回流功率优化对比分析

Comparative analysis of global current stress optimization and return power optimization of a three-level hybrid full-bridge DC-DC converter

三电平双有源混合全桥(hybrid three level full bridge,H-TLFB)DC-DC变换器在双重移相控制下存在回流功率和电流应力较大的问题,为此提出电流应力优化控制和回流功率优化控制两种优化控制策略。首先分析变换器4种工作模态,推导不同模态下电流应力、回流功率的表达式,通过对比求解全局内最小电流应力、最小回流功率对应最优移相比,并设计相应优化控制策略。然后基于相同传输功率段将两种优化控制策略进行对比分析,发现两种优化控制策略均可在全功率传输内对变换器进行优化。当1/2<p<2/3时,两种优化控制对电流应力的优化等效,当0<p<1/2时,两种优化控制对回流功率的优化等效。最后通过实验验证了理论分析的有效性和正确性。

Under dual phase shift control,the DC-DC converter of the hybrid three-level full bridge(H-TLFB)DC-DC converter has the problem of large reflux power and current stress.Thus two optimized control strategies of current stress optimization control and return power optimization control are proposed.First,this paper analyzes four working modes of the converter,derives the current stress and return power expression under different modes,solves the minimum current stress in the global area by comparison,the minimum return power corresponds to the optimal shift,and designs the corresponding optimization control strategy.Then it compares and analyzes the two optimized control strategies based on the same transmission power segment,finding that the two optimized control strategies can be optimized in the full power transmission.When 1/2<p<2/3,the optimization of the current stress of the two optimized controls is equivalent,and when 0<p<1/2,the two optimization controls are equivalent to the optimization of the return power.Finally,the effectiveness and correctness of the theoretical analysis are verified by experiment.