A solar photovoltaic system comprising: a plurality of PV subsystems connected together in parallel; each PV subsystem comprising: at least one PV array; and at least one PV inverter configured to generate at least one of single-phase or multi-phase AC active power in response to available PV array active power; and a PV control system configured to generate an active power output rate control signal based on a monitored rate of change of collective active power output generated via the plurality of PV subsystems and a desired collective output 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 to control a rate of change of one or more operating parameters of individual PV subsystems; characterised in that each PV subsystem further comprises a power output level ramp rate control mechanism arranged to minimize an error between a generated power level command signal and an actual power level command signal received by a PV subsystem inverter, wherein the error is obtained at a difference junction and amplified before being integrated by an integrator with respect to time to yield a ramped signal, wherein the ramped signal is communicated to the PV subsystem inverter as the actual power level command signal; said power output level ramp rate control mechanism further including a rate-limiter configured to limit the input to the integrator, the rate-limiter configured such that an output of the rate-limiter is limited by a maximum value defined by an upper bound of the rate-limiter, the power output level ramp rate control mechanism configured to control the power output level ramp rate of the PV subsystem independently of each of the other PV subsystems in response to the active power output rate control signal such that the rate of change does not exceed the upper bound of the rate-limiter. a plurality of PV subsystems connected together in parallel; each PV subsystem comprising: at least one PV array; and at least one PV inverter configured to generate at least one of single-phase or multi-phase AC active power in response to available PV array active power; and at least one PV array; and at least one PV inverter configured to generate at least one of single-phase or multi-phase AC active power in response to available PV array active power; and a PV control system configured to generate an active power output rate control signal based on a monitored rate of change of collective active power output generated via the plurality of PV subsystems and a desired collective output 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 to control a rate of change of one or more operating parameters of individual PV subsystems; characterised in that each PV subsystem further comprises a power output level ramp rate control mechanism arranged to minimize an error between a generated power level command signal and an actual power level command signal received by a PV subsystem inverter, wherein the error is obtained at a difference junction and amplified before being integrated by an integrator with respect to time to yield a ramped signal, wherein the ramped signal is communicated to the PV subsystem inverter as the actual power level command signal; said power output level ramp rate control mechanism further including a rate-limiter configured to limit the input to the integrator, the rate-limiter configured such that an output of the rate-limiter is limited by a maximum value defined by an upper bound of the rate-limiter, the power output level ramp rate control mechanism configured to control the power output level ramp rate of the PV subsystem independently of each of the other PV subsystems in response to the active power output rate control signal such that the rate of change does not exceed the upper bound of the rate-limiter.