Design and Comparison of Control Methods for Grid-Connected Solar Converters

This paper presents the results of comparing control methods for a single-phase grid-connected converter with a two-stage structure (DC-DC and DC-AC) in solar power application. The DC-DC stage plays an important role in optimizing capacity based on the maximum power point tracking (MPPT) on the solar panel. The Perturb & Observe (P&O) method is used for the DC-DC converter to find the maximum power point. DC-DC converter transmits power from a low DC voltage side to higher DC voltage side compling with the requirements for the DC-AC converter working properly. The DC-AC stage with the L filter has the role of receiving power from the DC-DC converter and transmitting power to the grid. There are some methods to control a DC-AC grid-connected converter. In this paper the three typical control methods, namely voltage-oriented control (VOC), proportional resonant controller-based control (PRC), and flexible power control (FPC) are presented and compared to point out the merits and disadvantages of each technique. As a result, the insight and application range of each control technique are provided. Converters are implemented and tested in Matlab-Simulink platform so that results are reliable.