A method of controlling power provided by a generator to an end system in which power is diverted from the output of said generator to an auxiliary system during periods of excessive power output from the generator. The diverted power is stored in an energy store and, during periods of lower power output from the generator, is returned to the end system by discharging the energy store. The diversion and return of power is controlled to maintain the power delivered to the end system at a desired mean power level. Diversion of power from the generator also has the effect of preventing the generator from producing excessive voltage levels.