1. A solar photovoltaic (PV) control system comprising: a plurality of PV subsystems connected together in parallel; a PV system power sensing mechanism configured to monitor instantaneous collective output active power generated via the plurality of PV subsystems connected together in parallel and generate a sequence of instantaneous collective output active power signals there from over a desired period of time; and a rate controller, wherein the rate controller is programmed to monitor a rate of change of collective active power output generated via the plurality of PV subsystems in response to the sequence of instantaneous collective output active power signals and control the rate of change of collective active power output generated via the plurality of PV subsystems by generating an active power output rate control signal based on the monitored rate of change of collective active power output generated via the plurality of PV subsystems and a desired collective active power change rate for the plurality of PV subsystems and communicating the active power output rate control signal to the plurality of PV subsystems; wherein each PV subsystem comprises a corresponding power output level ramp rate control mechanism programmed to control its power output level ramp rate independent from every other PV subsystem power output level ramp rate in response to the active power output rate control signal, and further to prevent its power output rate of change from exceeding ramp rate limits set by the rate controller while maintaining the desired collective active power change rate for the plurality of PV subsystems.