In this study, a novel double-loop control strategy is proposed to improve performance of switched reluctance generator (SRG) systems. The proposed double-loop control contains a power loop to control output power and an efficiency loop to optimise system efficiency. Development of the double-loop control contains three parts. First, a modified angle–voltage control (MAVC) scheme is developed to control phase current over the entire operating range. Second, firing parameters are optimised to enlarge the output power range when the SRG is controlled by MAVC. The turn-off angle is calculated by a simplified model; the turn-on angle and the DC-link voltage are optimised by differential evaluation algorithm. Third, an online mechanical power estimator is designed, with which the input mechanical power can be estimated for online efficiency optimisation in the efficiency loop. In the end, simulation and experimental results are presented to validate resulting improvements of the proposed control strategy.