多相交错并联自均流高增益DC/DC变换器及其控制策略

Multiphase interleaved parallel current sharing high-gain DC/DC converter and its control strategy

针对多相交错并联高增益DC/DC变换器在传统固定相移(2π/M)控制方式下,变换器会随着相数M的增加其只能在有限占空比范围(M-1)/M≤D<1内实现各相电流均流的问题,依据在多相变换器拓扑内电容电荷平衡原理以及各相电流均流条件,提出了一种可变移相的自动均流控制策略。所提控制策略只需任意两相相邻相位差φ满足2π(1-D)≤φ≤2πD条件,即可使得任意M(M≥2)相交错并联高增益DC/DC变换器在占空比[0.5,1)范围内均能实现各相电流自动均流。此外,对多相变换器中的电容电压纹波、电感电流纹波、电压增益、各相电流以及开关器件的应力进行了详细分析。最后,以四相高增益DC/DC变换器为例进行了模态分析,并搭建了一台低压输入/高压输出、功率300W的实验样机,实验结果验证了所提控制策略的有效性和正确性。

As the traditional fixed phase shift control method for multiphase interleaved parallel high-gain DC/DC converters can only achieve current sharing in the finite duty cycle range(M-1)/M≤D<1 with increasing the number of phases M,a variable phase-shift control strategy was proposed,based on the ampere-second balance principle of the multiphase converter topology and the current sharing condition of each phase.Under the proposed control strategy,the M(M≥2)phase converter can operate in duty ratio varying from 0.5 to 1 with automatic current sharing among phases,which only requires the phase shiftφof two adjacent phases to satisfy 2π(1-D)≤φ≤2πD.Next,the capacitor voltage ripple,inductor current ripple,voltage gain,phase currents and switching device stresses of the multiphase converter were analyzed in detail.Finally,the operating modes for four-phase converter was analyzed,and a 300W,low-voltage input/high-voltage output,four-phase laboratory prototype was implemented.The experimental results verify validity and accuracy of the proposed control strategy.