Rectangular current commutation and open-loop control for starting of a free-piston linear engine-generator

Starting a free-piston linear engine-generator consists of reciprocating a freely moving piston-magnettranslator assembly between two oppositely placed engine cylinders to initiate combustion. To provide for the reciprocating force, the machine is operated as a brushless linear motor. A starting str...

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Bibliographic Details
Main Authors: S.A., Zulkifli, M.N., Karsiti, A.R.A., Aziz
Format: Conference or Workshop Item
Language:English
Published: 2008
Subjects:
Online Access:http://scholars.utp.edu.my/id/eprint/276/
http://scholars.utp.edu.my/id/eprint/276/1/paper.pdf
Description
Summary:Starting a free-piston linear engine-generator consists of reciprocating a freely moving piston-magnettranslator assembly between two oppositely placed engine cylinders to initiate combustion. To provide for the reciprocating force, the machine is operated as a brushless linear motor. A starting strategy is proposed which utilizes the air-spring quality of the engine cylinders prior to combustion: by energizing the coils with fixed DC voltage and by open-loop, rectangular commutation of injected current, sufficiently high motor force is produced to reciprocate the piston-magnet assembly in small amplitudes initially. Due to repeated compression-expansion of the engine cylinders and constant application of motoring force in the direction of natural bouncing motion, the translator's amplitude and compression pressure is expected to grow - due to mechanical resonance - to finally reach the required parameters for combustion. This work discusses the electrical aspects of the starting strategy, considers control possibilities, builds a model of the electrical subsystem and presents simulation and validation tests of the integrated model for starting investigation. © 2008 IEEE.