基于效率模型的DC-DC变换器并联系统电流分配策略

A Current Distribution Strategy for Parallel DC-DC Converters Based on the Efficiency Model

由相同或不同功率等级的DC-DC变换器构成的分布式电源系统运行时,为实现能源的有效利用,应尽可能的提高系统的运行效率。基于平均损耗计算推导Buck变换器在连续电流导通模式下的效率函数模型,给出效率函数模型的参数计算方法。为优化并联系统的运行效率,提出基于效率模型的并联模块电流分配策略。设计Buck变换器并联系统的优化目标函数,给出并联模块电流分配的计算方法,分析模块电流的约束条件,给出并联运行模块数的调节方法。完成数值仿真与系统实验,试验结果表明,与采用平均电流分配策略相对比,提出的电流分配策略能够提高并联系统的运行效率。

For utilizing energy availably, the system efficiency of distributing power supply ought to be improved possibly; the system is composed of DC-DC converters with uniform or different power grade. In this paper, the efficiency model of Buck converters in the continuous conduction mode （CCM） was educed based on the average loss, and the calculation method of parameters for the efficiency model was given. For optimizing the operation efficiency of the paralleled system, the current distribution strategy based on the efficiency model was presented. The optimization object fimction of the Buck converter paralleled system was designed. The calculation method of module currents was deduced and the constraint condition of currents was analyzed. The adjust method of the paralleled module number was also given. Numerical simulations and experiments were done. It is validated that the efficiency of the paralleled system can be improved adopting the current distribution strategy based on efficiency optimization, which is compared with the system adopting the average current distribution.