Linear Compressor Motor Control for Uneven Fatigue
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Solution Overview
Problem
Linear compressors face issues with uneven extension of elastic elements, leading to increased fatigue and reduced operational life, due to imbalanced force distribution during piston oscillation, which can cause head crashing and damage components, and existing solutions like sensors are impractical due to contamination risks and increased costs.
Innovation Solution
A method of operating a linear compressor involves supplying a time-varying voltage to the motor and determining uneven fatigue conditions, applying a limiting force in the negative axial direction using a direct current voltage to mitigate excessive spring extension and prevent part fatigue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor is used to measure piston stroke length, then measurement precision is improved, but device complexity and reliability deteriorate due to contamination risks and sensor failure
Solution Approach 1:
The patent replaces the mechanical sensor-based measurement system with an electrical control system that uses the motor's inherent electrical characteristics (current, voltage, frequency) to determine piston position and oscillation parameters. This substitution eliminates the need for physical sensors that would require piercing the hermetic seal, thereby maintaining measurement capability while improving reliability and avoiding contamination risks.
2Productivity
If the piston oscillation is allowed to proceed without control, then productivity is improved, but reliability deteriorates due to head crashing and component damage
Solution Approach 1:
The patent implements a feedback control system that continuously monitors the piston's oscillation parameters (amplitude, frequency, position) through electrical measurements and adjusts the motor's driving parameters in real-time. This feedback mechanism prevents head crashing by detecting approaching extreme positions and adjusting the oscillation accordingly, while maintaining optimal compression performance through continuous parameter optimization.
Solution Approach 2:
The patent employs dynamic adjustment of the motor's electrical parameters (voltage, current, frequency) to control the piston's oscillation characteristics. By dynamically varying these parameters based on real-time conditions, the system maintains optimal compression efficiency while preventing mechanical contact between the piston and cylinder head, thereby protecting components from damage.
3Ease of operation
If the elastic element extension is allowed to be unbalanced, then ease of operation is improved, but reliability deteriorates due to increased fatigue and part failure
Solution Approach 1:
The feedback control system monitors the piston's oscillation symmetry and the elastic element's extension patterns, adjusting the motor's driving parameters to balance the extension distribution. By detecting asymmetries in real-time and compensating through parameter adjustment, the system maintains operational freedom while preventing excessive or unbalanced extension that would lead to fatigue and failure.
Solution Approach 2:
The patent changes the electrical parameters (voltage, current, frequency) supplied to the motor to optimize the piston's oscillation characteristics. By adjusting these parameters, the system achieves balanced elastic element extension while maintaining free oscillation, thereby reducing fatigue loading and extending the lifespan of the elastic element without compromising operational ease.
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 approach reduces uneven fatigue and extends the operational life of linear compressor components by maintaining balanced force distribution and preventing excessive spring extension, thereby enhancing reliability and performance.
Implementation Method 1
The driving coil receives a current that generates a force for oscillating the piston
Implementation Method 2
An elastic element, such as a spring, may be provided to aid in such oscillation
Implementation Method 3
During motion of the piston within the chamber, the piston compresses refrigerant
Data Source
AI summary
A linear compressor and methods of operation, for example, to control extension of the linear compressor, are provided herein. A method may include supplying a time varying voltage to a motor of the linear compressor, determining an uneven fatigue condition at the linear compressor, and applying a limiting force at the motor in a negative axial direction in response to the determining step.