The inner loop control strategies for photovoltaic(PV)power generation systems include maximum power point tracking(MPPT)and DC bus voltage support strategy.Switching between these two control strategies often leads to DC bus overvoltage

causing system oscillations and

in severe cases

PV shutdown.This paper proposes a novel differential control strategy for output power based on the output characteristics of the photovoltaic array.By this strategy

PV can switch the control object naturally without switching the control strategy.Thus

the DC bus voltage oscillation can be reduced and the system performance can be improved.Additionally

an outer loop controller adopts droop control to ensure an even output power distribution across multiple distributed PV systems.The feasibility of this control strategy is substantiated through a simulation model.