Method for controlling the rotational speed fluctuation of a compressor
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Solution Overview
Problem
Severe speed fluctuation in compressors due to unstable load torque, often caused by refrigerant system failures or design flaws, leads to unstable operation, excessive noise, and adverse user experiences, with prior art methods failing to fundamentally address rotational speed fluctuations.
Innovation Solution
A method controlling compressor speed by filtering shaft errors using Fourier series expansion and low-pass filters to eliminate harmonic components, compensating angular velocity in phase-locked loops, and adjusting torque in speed loops to stabilize compressor operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If prior art control methods are used for compressor speed fluctuation, then basic control function is maintained, but speed fluctuation suppression effectiveness is insufficient
Solution Approach 1:
The patent segments the shaft error signal into multiple harmonic components using Fourier series expansion, allowing selective filtering of specific frequency components that cause speed fluctuation. This segmentation enables targeted suppression of problematic frequencies while preserving other operational characteristics.
Solution Approach 2:
The patent introduces an intermediary processing stage between the phase-locked loop and the compressor control system. This intermediary includes harmonic analysis and selective filtering mechanisms that process the shaft error signal before it reaches the speed control loop, effectively mediating the control action to reduce speed fluctuation.
2Reliability
If shaft error filtering is applied to eliminate harmonic components, then speed fluctuation is reduced, but control response time may be affected
Solution Approach 1:
The patent employs periodic harmonic analysis at specific frequencies identified through Fourier series expansion. By focusing filtering efforts on specific periodic components rather than applying continuous broad-spectrum filtering, the system maintains faster response to non-periodic control demands while suppressing periodic speed fluctuations.
Solution Approach 2:
The patent dynamically adjusts filtering parameters based on the detected harmonic content of the shaft error signal. When significant harmonic components are detected, filtering is applied; when the signal is clean, filtering is reduced or bypassed, thereby maintaining fast response time while achieving stability when needed.
3Reliability
If angular velocity compensation is implemented in phase-locked loop, then speed fluctuation is suppressed, but control system complexity increases
Solution Approach 1:
The patent extracts only the problematic harmonic components from the shaft error signal using Fourier series expansion and selective filtering. By taking out only the specific frequency components that cause speed fluctuation rather than processing the entire signal, the complexity addition to the phase-locked loop is minimized while achieving effective suppression.
Data Source
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AI summary
Disclosed is a method for controlling rotational speed fluctuation of a compressor. The method comprises processes of controlling the compressor according to a real-time angular speed and according to a torque. The process of controlling the compressor according to the real-time angular speed involves: carrying out filtering processing on an axis error to obtain an angular speed compensation quantity; compensating the angular speed compensation quantity to an output angular speed of a phase-locked loop adjuster, so as to obtain a compensated angular speed output quantity; and correcting the real-time angular speed according to the compensated angular speed output quantity, and controlling the compressor according to the corrected real-time angular speed. The process of controlling the compressor according to the torque involves: calculating the difference between a target angular speed fluctuation quantity and the output angular speed of the phase-locked loop adjuster, so as to obtain a first angular speed difference value; carrying out filtering processing on the first angular speed difference value to obtain a filtered angular speed; inputting the filtered angular speed to a speed loop adjuster to obtain an output torque; and controlling the compressor according to the output torque.