This paper presents a comparive analysis between four Maximum Power Point Tracking (MPPT) algorithms in centralized grid-tied Photovoltaic (PV) systems. The algorithms are used to control the duty cycle of a DC-DC converter in order to boost the output voltage of the PV generator and guarantee the operation of the solar panels in the Maximum Power Point (MPP). Three of the analyzed algorithms correspond to the classical Perturb and Observe (P&O) method, the Incremental Conductance (IC) technique and the Constant Voltage (CV) method. The fourth analyzed algorithm is a modification of the classical P&O method and it has been designed to improve the tracking of the MPP under voltage disturbances at the DC-side capacitor (interface between the DC-DC and the DC-AC stage). The performance of the MPPT techniques is compared through simulations in PSIM under two conditions: sudden changes of irradiance and a distortion of second order in the voltage at the DC-side capacitor. The comparative analysis is made according to some criterias such as the number of sensors, the rise time and the efficiency.