Grid-connected photovoltaic (PV) systems are increasingly attracting the attention of industry and academia as a means of providing an alternative to conventional fossil-fuel generation. In grid-connected PV systems, a key consideration is the design and operation of power converters and how to achieve high efficiency for different power configurations. The requirements for converter connection include: maximum power point, high efficiency, control power injected into the grid, and low total harmonic distortion of the currents injected into the grid. Consequently, the performance of the inverters connected to the grid depends largely on the control strategy applied. This chapter presents a comprehensive overview of power converter topologies and control structures for grid-connected PV systems.