Gas Compressor Inverter Control Avoiding Resonance Frequencies
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Solution Overview
Problem
Inverter control operations in gas compressors often result in rotational speeds passing through resonance frequencies, leading to potential resonance and increased vibration and noise, which compromises compressor reliability.
Innovation Solution
A compressor system with an inverter, check valve, pressure detection means, and controller that adjusts output frequency based on detected pressure, avoiding specific frequencies associated with resonance by using a pressure margin for frequency switching, thereby reducing the occurrence of resonance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the compressor operates at variable rotational speeds to maintain predetermined pressure, then the pressure control precision is improved, but the rotational speed passes through resonance frequencies causing resonance and vibration
Solution Approach 1:
The patent extracts and removes the harmful resonant frequency range from the operational frequency spectrum. The controller is configured to exclude a specific resonant frequency range (fr1 to fr2) from the frequency adjustment operations, thereby separating the harmful vibration frequencies from the useful pressure control frequencies. This allows the compressor to maintain precise pressure control without passing through resonant conditions.
Solution Approach 2:
The patent changes the operational parameters by defining a frequency exclusion zone. When the target frequency for pressure control falls within the resonant range (fr1-fr2), the controller adjusts the frequency to values outside this range while maintaining pressure control. This parameter modification approach allows the system to avoid resonance while preserving the primary function of pressure maintenance.
2Stability of the object's composition
If the rotational speed is adjusted frequently to maintain pressure, then the pressure stability is improved, but the frequency passes through resonance range more often increasing resonance occurrence
Solution Approach 1:
The patent removes the resonant frequency range (fr1-fr2) from the available frequency adjustment range. The controller is designed to select frequencies only from the safe ranges (below fr1 or above fr2), thereby extracting the harmful resonant frequencies from the operational spectrum. This prevents repeated passage through resonance while maintaining pressure stability through frequency adjustments in the non-resonant ranges.
Solution Approach 2:
The patent implements preliminary action by pre-defining the resonant frequency range (fr1-fr2) as excluded zones before operational frequency adjustments are made. The controller proactively avoids these frequencies by selecting target frequencies from safe ranges, preventing resonance occurrence before it can happen. This anticipatory approach maintains pressure stability without the need for reactive resonance avoidance.
3Adaptability or versatility
If the frequency adjustment range is widened to improve pressure control flexibility, then the adaptability is improved, but the range includes more resonance frequencies increasing vibration risk
Solution Approach 1:
The patent segments the frequency spectrum into safe operational ranges and harmful resonant ranges. The frequency adjustment range is divided into two safe zones (below fr1 and above fr2) separated by the excluded resonant zone (fr1-fr2). This segmentation allows the controller to maintain wide adaptability for pressure control while systematically avoiding the vibration-prone resonant frequencies through the defined frequency exclusion mechanism.
Data Source
AI summary
In order to reduce operation in a rotation-prohibited frequency range and to prevent resonance in a gas compressor wherein inverter control is performed, this gas compressor has: a compressor main body that compresses a gas; a motor that rotationally drives the compressor main body; an inverter that changes the rotational speed of the motor; a check valve arranged downstream from the compressor main body; a pressure detection means that detects load-side pressure downstream from the check valve; and a control device that, in accordance with the pressure detected by the pressure detection means, controls the frequency output by the inverter. The control device performs a control whereby compressed gas having a prescribed pressure is generated/maintained by increasing/decreasing the frequency, and when the frequency that generates the compressed gas having the prescribed pressure includes a specific frequency, the inverter's output frequency is increased or decreased when the pressure detected by the pressure detection means reaches a pressure corresponding to a frequency that has a more constant pressure width than the prescribed pressure and does not include the specific frequency.