Characteristics of linear compressors under current source excitation

The current paper analyses the steady-state and dynamic performance characteristics of a direct-drive linear vapour compressor, and it is shown that it operates most efficiently and stably at resonance under current source excitation. Further, the piston amplitude and top clearance vary almost linearly with the amplitude of the excitation current. These features facilitate efficient operation and control of the linear compressor without the need for a discrete piston position sensor, and provide a simple means of regulating the cooling capacity according to the refrigerator demand. The findings are validated by measurements on a prototype linear compressor.