Linear compressor and set point control method
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Solution Overview
Problem
Existing linear compressors face issues with mechanical crashing due to piston motion, limited adjustable stroke length, and fixed cooling capacity, which affects efficiency and durability.
Innovation Solution
A linear compressor with a controller that adjusts the resting setpoint and cooling capacity by injecting direct current (DC) voltage to modify the piston's motion, enhancing stroke length and efficiency without altering the physical structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional compressor designs are used, then structural simplicity is maintained, but performance at low speeds and part-load conditions deteriorates
Solution Approach 1:
The piston motion is changed from conventional reciprocating motion to simple linear motion through a guide mechanism. The piston is constrained to move only in the axial direction along the cylinder bore, eliminating side forces and improving performance at low speeds and part-load conditions while maintaining structural simplicity
Solution Approach 2:
The compressor is divided into multiple cylinders arranged in parallel, each with its own piston driven by a common drive mechanism. This modular approach allows independent optimization of each cylinder's performance while maintaining overall system simplicity
2Object-generated harmful factors
If reciprocating piston motion is used, then conventional design is maintained, but harmful side forces and vibrations increase
Solution Approach 1:
The piston is guided to move in a straight line along the cylinder axis using a guide mechanism, eliminating the angular motion and side forces characteristic of conventional reciprocating compressors. This reduces vibrations and harmful forces while simplifying the motion mechanism
Solution Approach 2:
The guide mechanism acts as a constraint that counteracts the tendency of the piston to generate side forces, directing all motion purely in the axial direction and eliminating harmful lateral vibrations
3Productivity
If expandable clearance volume is used, then volumetric efficiency at part-load is improved, but device complexity increases
Solution Approach 1:
The clearance volume is made variable through a mechanism that adjusts the piston rod cross-sectional area or position, allowing optimization of volumetric efficiency at different load conditions without requiring complex expandable volume mechanisms
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves operational efficiency, reduces mechanical wear, and increases cooling capacity while maintaining high efficiency, leading to energy savings and extended appliance lifespan.
Implementation Method 1
a drive mechanism is provided which has a rotational movement which is transformed into a linear movement of the piston by a guide mechanism
Data Source
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AI summary
A linear compressor and methods of operation, for example, to control a setpoint and vary cooling capacity of the linear compressor, are provided herein. An appliance may include a linear compressor having a reciprocating piston movable in a negative axial direction toward a chamber and positive axial direction away from the chamber. The appliance may further include a motor operatively coupled to the reciprocating piston, the motor having a resting setpoint, an inverter configured to supply a variable frequency waveform to the motor, and a controller configured to control the variable frequency waveform. The controller may be configured to direct a positive DC voltage to the motor to shift the resting setpoint to increase a cooling capacity of the linear compressor.