System for adjusting resonance frequencies in a linear compressor

Abstract

A system for adjusting resonant frequencies in a linear compressor comprising, in the interior of a shell: a linear motor: a cylinder; a piston reciprocating inside the cylinder; and an actuating means operatively coupling the piston to the linear motor, said system comprising: a detecting means to detect a load imposed to the linear motor, in an operational condition of the latter related to the gas pressure in the discharge thereof; and a frequency adjusting means operatively associated with the detecting means and with the resonant assembly, in order to define, as a function of said operational condition, a frequency adjustment, by varying at least one of the values related to the mass of the resonant assembly and to the average stroke of the piston, to a value of the mechanical resonance frequency corresponding to the electrical supply frequency.

Description

FIELD OF THE INVENTION [0001] The present invention refers to a system for controlling and adjusting the resonance frequencies in a linear compressor of the type used in small refrigeration appliances, such as refrigerators, freezers, water fountains, etc. BACKGROUND OF THE INVENTION [0002] Linear compressors present a mechanical resonance frequency that is defined by the spring constant and by the masses of the movable components of said compressor when the latter is working with no gas load to be refrigerated (unloaded), i.e., with no gas being pumped. The mechanical resonance frequency of the mass-spring system of the compressor is a function of the mass-spring project thereof and defines the natural mechanical resonance frequency of the compressor. [0003] The mechanical resonance frequency during the operation of the compressor, with the latter pumping gas under a determined pressure ratio, said pressure ratio being defined as the discharge pressure divided by the suction pressu...

AI Technical Summary

Benefits of technology

[0017] a system for adjusting the resonance frequencies in a linear compressor, which controls and conducts the mechanical resonance frequency of the compressor, at least in determined operational conditions, to values that are substantially close to the electrical supply frequency of the compressor, without presenting the high costs and high energy losses of the electronic control systems.

[0018] It is a further object of the invention to provide a system such as mentioned above, which maintains the dead volume of the compressor at a minimum value during the operation thereof, maintaining an adequate volumetric yield, with minimum energy loss.

Problems solved by technology

In determined situations, the loss of balance between the electrical and mechanical frequencies in the compressor results, for the latter, in a higher need of energy to maintain the pumping of gas.

In a situation in which the refrigeration appliance is conducted from a turn-off condition to a turn-on condition, the refrigeration system of this appliance is submitted to high pressure peaks, with maximum pumping capacity, which increases the mechanical resonance frequency of the compressor, causing unbalance between said mechanical resonance frequency and the electrical supply frequency of the power system.

Since the motor yield is a function of its effort to operate, there is loss of motor efficiency whenever the mechanical resonance frequency is not equalized with the electrical supply frequency of the power system.

However, this solution is expensive and presents energy loss.

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