Electromagnetic Process Analysis And Improvement Of A Free Piston Engine Generator

Free piston engine generation(FPEG)is a new type of vehicle power generation device.It has the advantages of high energy utilization and strong fuel adaptability.It has been widely concerned and studied in recent years.This paper took the third-generation FPEG prototype developed by our group as the research object,and the electromagnetic process analysis and improvement design of the system were carried out.The work includes the following aspects:(1)Based on the existing FPEG prototype,the electromagnetic process of its motor system was modeled.Combined with mathematical models of other parts of FPEG,a joint simulation model was established.The model was verified based on experimental data,and then the electromagnetic process of the motor system was analyzed,including EMF,loss characteristics of surface mounted permanent magnet moving coil linear generator(SPM-MCLG),and current,loss characteristics of boost bidirectional reversible power converter(B-BRPC).(2)The cause of loss and the magnetic circuit composition of the original motor scheme SPM-MCLG were analyzed,and an improved scheme of inner permanent magnet moving coil linear generator(IPM-MCLG)was proposed.The structural parameters of the improved solution was determined.The thrust,EMF,efficiency characteristics of the improved scheme were analyzed,and compared with the original scheme.(3)In order to simplify the circuit structure of the original converter scheme B-BRPC,an improved scheme based on the H-bridge bidirectional reversible power converter(H-BRPC)was proposed.The modulation mode,switching frequency and current waveform of the improved scheme wree determined.The physical model of the improved scheme was established,and its characteristics in the electromagnetic process were analyzed in terms of power,loss and energy flow,and compared with the original scheme.(4)Based on the improvement scheme of the motor and the converter,the development of the prototype of the improvement scheme was completed,and the prototype test platform was built;the experimental research of the prototype was carried out,and the test results were compared with the simulation results.Compared with the original scheme,the efficiency of the motor and converter of the improved scheme has been increased by 20.1% and 3.4%,and the total efficiency of the electromagnetic process of FPEG’s motor system has been improved by 21.4%.