光伏电池阵列输出功率受光照强度和温度变化的影响，因此最大功率点跟踪（MPPT）技术广泛应用于光伏系统中。在所有最大功率点(MPP)控制策略中，扰动观察（P&O）MPPT算法因易实现被广泛应用，然而它的缺点是在稳定工作状态下工作点通过MPP 时会导致能量振荡损耗，并且在光照强度或温度发生突变时表现较差的动态响应。在本文中，提出一种改进型变步长扰动观察MPPT 算法，此方法依据工作点动态调整步长变化，与传统固定步长方法比较，本文提出的方法能有效地提高MPPT 速度和转换效率，通过仿真和实验结果分析，验证了此改进算法的可行性。-PV array output power by light intensity and temperature changes, so the maximum power point tracking (MPPT) technology is widely used in photovoltaic systems. In all the maximum power point (MPP) control strategy, the perturbation and observation (P &　O) MPPT algorithm because easy to implement is widely used, but its disadvantage is the steady-state operating point by the MPP causes energy oscillations loss, and in the light intensity or temperature mutated poor performance dynamic response. In this paper, we propose a modified variable step size perturbation and observation MPPT algorithm, this method is based on dynamically adjusting the operating point changes in steps, with the traditional fixed-step methods, the proposed method can effectively improve the speed and efficiency MPPT, The simulation and experimental results verify the feasibility of this algorithm.