The perturb & observe (P&O) algorithm is very popular for maximum power point tracking (MPPT) for solar photovoltaic (PV) systems. However, it has tracking problems during varying irradiations as well as the nuisance of oscillations around the maximum power point (MPP). This work introduces a circle center-line concept based P&O (CCCP&O) algorithm for MPPT, where, the concept of circle and its center are combined with the PO algorithm. This algorithm tends to reduce the number of iterations taken to reach the MPP, which reduces settling time. Moreover, the problem of large oscillations around the MPP is eliminated by using the concept of flexible step size. The algorithm initializes with standard PO, but utilizes a approach of diameter equivalence of a circle as a procedure to reach next operating point on the power-voltage plot. Therefore, the iterations required to get to the MPP are reduced substantially. The MPP changes with change in solar irradiance, therefore, a concept of artificial envelope around the P-V curve is used to improve tracking of the algorithm during varying irradiances. The overall performance of the algorithm is demonstrated and compared in simulation using SIMULINK MATLAB as well as also shown experimentally in a developed hardware prototype. © 2004-2012 IEEE.