Solar power systems and methods utilize DC power transmission and centralized power inversion. The solar power systems include a photovoltaic (PV) bus system and a fixed bus system. The PV system utilizes a control mode handoff control method, which includes determining that a local maximum power point tracking (MPPT) control is enabled; in response to determining that the local MPPT control is enabled, starting an MPPT mode timer; performing local MPPT; determining that the MPPT mode timer is greater than a predetermined period; and, in response to determining that the MPPT mode timer is greater than a predetermined period, handing off MPPT control to the next MPPT controller. The distributed MPPT control method may include sequential MPPT control, adaptive ΔV MPPT control, and/or power limiting control. The fixed bus system includes PV string-level MPPT controllers and a fixed DC input central inverter or multiple fixed DC modular inverters.