A new maximum power point tracking (MPPT) algorithm of photovoltaic (PV) system is proposed in this paper. It is well suited for microinverter applications especially under partial shading conditions. It relies on voltage measurements on each substring of PV module. The substring with the highest voltage is set as the guiding unit and the global maximum power point (GMPP) is determined based on it. The proposed method can be implemented in any of the existing inverter configurations, with the only additional requirement being the voltage sensors across each substring, i.e., across each bypass diode of the modules. The proposed algorithm referred to as the maximum-voltage-unit-guided MPPT (MVUG-MPPT) is simple to implement and results in superior performance in terms of MPPT accuracy and speed under partial shading. The detailed development of the algorithm and its implementation are described. Validation of the proposed methods using extensive numerical simulations in PLECS and comparison with other MPPT approaches are also presented.