A Swing Start-up Strategy of Modular Free Piston Linear Generator Based on State Identification

This paper proposes a modular free-piston linear generator(M-FPLG) which consists of a combustion chamber, air spring, and linear motor. In the start-up stage, the motor needs to generate a lot of electromagnetic force to push the piston to the designated position, while the motor thrust of the M-FPLG is insufficient for the purpose of lightweight design, so it is difficult for the traditional position control strategy to achieve the high compression ratio required during the start. This paper presents a swing startup strategy for M-FPLG based on state identification. By using the principle of swing, the electromagnetic force is adjusted according to the state, so that the energy of the system increases continuously in the process of reciprocating motion until reaching the starting requirements. Simulation analysis and experimental verification are carried out for the proposed control strategy, whose results prove the effectiveness of the control strategy.