Linear Compressor Electro-Magnetic Spring Resonant Control
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Solution Overview
Problem
Linear compressors in refrigerator appliances face inefficiencies due to high friction from moving parts and require complex active control for piston motion, which is costly and inefficient, especially when operating at resonant conditions.
Innovation Solution
A linear compressor design utilizing an electro-magnetic spring to urge the piston towards a default position, eliminating the need for mechanical springs and simplifying control by using a driving coil and spring magnets to operate at a resonant frequency without complex controls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a piston and crankshaft mechanism is used to compress refrigerant, then the compression function is achieved, but the large number of moving parts generates large friction forces resulting in poor efficiency
Solution Approach 1:
The patent replaces the traditional mechanical piston-crankshaft system with a linear motor system consisting of a piston, driving coil, and electro-magnetic spring. This substitution eliminates the crankshaft and associated moving parts, significantly reducing friction losses while maintaining the refrigerant compression function through direct linear motion of the piston driven by electromagnetic forces.
2Productivity
If linear compressors use mechanical springs to urge the piston towards a default position, then the piston can oscillate at resonant frequency, but the fixed spring constants make the system inefficient
Solution Approach 1:
The patent replaces the static mechanical spring with a dynamic electro-magnetic spring system where the spring constant can be adjusted by controlling the current through the spring coil. This allows the system to adapt the spring constant to match different operating conditions and maintain optimal resonant operation, overcoming the limitation of fixed spring constants in mechanical springs.
Solution Approach 2:
The patent enables dynamic adjustment of the spring constant parameter by varying the current through the spring coil. This parameter change capability allows the electro-magnetic spring to adapt to different operating conditions, maintaining optimal resonant frequency and amplitude for maximum compression efficiency under varying loads and conditions.
3Measurement precision
If linear compressors require active control for every piston stroke to stop motion at either end, then precise control is achieved, but the control system becomes complex, expensive, and inefficient
Solution Approach 1:
The patent utilizes resonant vibration of the piston-mass-spring system to achieve automatic stopping at the extremes of travel. By operating at the natural resonant frequency of the system, the piston naturally comes to rest at the endpoints of its oscillation without requiring active control intervention, thereby simplifying the control system while maintaining precise position control.
Solution Approach 2:
The electro-magnetic spring system provides self-regulating behavior where the oscillating piston automatically stops at the extremes of its travel during resonant operation. This self-service mechanism eliminates the need for complex active control systems to manage piston positioning, reducing control complexity and cost while maintaining operational precision.
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
This design enhances efficiency by minimizing friction and reducing the complexity of control systems, allowing the compressor to operate effectively at a resonant condition with improved performance and reduced energy consumption.
Implementation Method 1
The driving coil receives a current in order to generate a force that slides the piston backward and forwards within a chamber to compress refrigerant
Implementation Method 2
An electro-magnetic spring includes at least one ferromagnetic tooth. Each ferromagnetic tooth of the at least one ferromagnetic tooth is positioned proximate a respective one of the at least one spring magnet. The electro-magnetic spring urges the piston assembly towards about the default position when the piston assembly is positioned away from the default position
Implementation Method 3
By adjusting the strength of the driving coil's force and the frequency of application of such force, the piston can slide within the chamber at a resonant frequency in which the amplitude of the piston's displacement can be maximized for the force applied to the piston
Data Source
AI summary
A linear compressor is provided. The linear compressor includes a casing that defines a chamber and a piston slidably received within the chamber of the casing. A driving coil is configured for selectively urging the piston to slide within the chamber of the casing. An electro-magnetic spring is configured for urging the piston towards a default position when the piston is positioned away from the default position. The electro-magnetic spring can permit the linear compressor to operate at a resonant condition.