Abstract: The invention relates to a control method and system comprising an electronic control unit (11) controlling the electric current power supply from an electric power source to a motor-compressor arrangement (12, 13); the electronic control unit comprises a conversion means which is connected to an inversion means (15) to supply the voltage demanded by the motor (12). A PWM pulse width regulator (16) generates the switching signals for all the switching elements of the unit (11) relating to said demanded voltage.

Abstract: It includes a piston (2) of markedly small diameter associated with a cylinder (3) of a compression chamber (4). It is characterised in that it includes a gas intake port (6) at a lateral zone of the cylinder (3) near the bottom dead centre point of the piston (2), a P-V optimisation valve (7) mounted inside the piston (2), and at least one hole (8) made inside the piston (2) in a radial direction that connects said intake port (6) with the P-V optimisation valve (7), in such a way that the at least one hole (8) is moveable along the intake port (6), permitting entry of the gas towards the compression chamber (4) during the piston intake stroke (2) and closure of the gas during the piston compression stroke (2). Increased energy efficiency of the compressor is achieved and the intake valve in the piston head is eliminated.