If P-V curves are two-peak curve or multi-peak curve, there will be an error of tracking maximum power point when using the common perturbation and observation.

• 如遮蔽效应使P-V曲线变为双峰或是多峰，使用一般惯用的扰动观察法，可能对追踪最大功率点造成错误的判断。