Structural parameters matching design for free-piston linear alternator

To propose a designing strategy for free-piston linear alternator, the matching relationships between the structural parameters and the performance parameters were analyzed following the moving characteristics of free piston, including the cylinder displacement and output power, the maximum combustion pressure and cylinder displacement, the compression ratio and output power, and the piston mass and electromagnetic load. According to the matching relationships, a designing strategy with total system parameters for free-piston linear alternator was constructed, and the main structural parameters of a test prototype, including piston mass, stroke length, compression ratio, bore and electromagnetic load, were determined. The effectiveness of the designing strategy was verified by simulations and tests of the prototype. It indicates that the maximum error of frequency between the operating observation and designing objective reaches 13.4%, the maximum error of combustion pressure 10.5% and the maximum error of output power 6%.