Employing dual scaling mode for adaptive hill climbing method on buck converter

For adaptive hill climbing method, variable stepping is achieved by sizing the change of power over the change of voltage (dP_PV/dV_PV) and change of power over change of D (dP_PV/dD) to appropriate step size using a properly tuned scaling factor. However, the photovoltaic (PV) power versus voltage curve has two different slopes which are the left-hand side of the maximum power point (MPP), and right-hand side of MPP (ROM). The fine-tuned scaling factor for the left-hand side PV slope has good performance at left-hand side of MPP (LOM) but can cause overshoot when system operates at the ROM; while scaling factor properly tuned for the right-hand side PV slope has good performance at ROM but slow voltage response when the system operates at LOM. Dual scaling factor technique is proposed to achieve good performance at LOM and ROM. Besides that, the drawback of implementing hill climbing method on buck converter is discussed, where using constant step size, the hill climbing method has small voltage response at point far from MPP but large voltage response at point near MPP. Based on the results obtained from a lab-scale prototype, it is proven that the proposed method is simple and effective.