DC—DC变换器作为光伏发电最大功率点跟踪(maximum power point tracking,MPPT)控制器的核心部分,其动力学特性对系统的性能产生影响。该文基于非线性动力学系统理论,建立了光伏发电最大功率点跟踪(maximum power point tracking,MPPT)交错并联Boost变换器的离散迭代映射模型,在此基础上采用分岔图、时域波形图、相轨迹图方法,研究了其动力学特性,并与一般Boost变换器特性进行比较。理论与实验结果均表明,在相同电路参数的情况下,与一般Boost变换器相比,交错并联Boost变换器的稳定域更大,电感电流和电容电压的纹波小、变化幅度小,更适用于光伏发电MPPT。
DC-DC converters are the core of controller of the maximum power point tracking (MPPT) for photovoltaic (PV) power, their dynamical characteristics will influence the system's stability. Based on the nonlinear dynamic system theory, the model of the discrete iterative map of the interleaved Boost converter (ILBC) in MPPT was derived. The study of the dynamical characteristics was made by bifurcation diagrams, time-domain waveforms and phase trajectories in the terms of the model, and the comparison between the interleaved Boost converter and the parallel-connected Boost converter (PCBC) was performed. Both the simulation and experiment results show that compared with the PCBC, the ILBC is larger in the stable-domain, smaller in inductor current ripple and capacitance voltage ripple and smaller in variation range of inductor current and capacitance voltage. Thus, the ILBC is more suitable than the PCBC in MPPT for PV generation.