Cascaded Adaptive Filters for Flow Controller Noise Attenuation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing noise attenuation methods in fluid control systems, such as passive filters, fail to effectively filter noise components correlated with pump speed changes, leading to unstable valve operations and inaccurate flow rate measurements due to pulsating fluid flows and vortex-induced perturbations.
Innovation Solution
The implementation of cascaded adaptive filters that generate a noise reference signal to separate and attenuate noise components from flow rate signals, using a combination of DC cancellers and adaptive noise cancelling filters to stabilize valve operations and provide accurate flow rate measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If passive filters are used to attenuate noise in the flow rate signal, then the noise attenuation is improved, but the rapid changes in flow rate measurements are undesirably attenuated causing inaccurate measurements
Solution Approach 1:
The patent transitions from static passive filters with fixed frequency characteristics to dynamic adaptive filters that continuously adjust their filtering parameters based on the actual noise characteristics in the flow rate signal. The adaptive filter adapts its transfer function in real-time to match the varying noise frequency and amplitude, allowing it to attenuate noise effectively while preserving rapid flow rate changes.
Solution Approach 2:
The patent changes the filtering parameters dynamically by using an adaptive filter whose coefficients and transfer function are continuously adjusted based on the detected noise characteristics. The filter parameters are modified in real-time to optimize the balance between noise attenuation and signal preservation, unlike fixed passive filters with static parameters.
2Productivity
If the pump speed increases to improve productivity, then the flow rate increases, but the noise component frequency increases causing valve instability
Solution Approach 1:
The patent implements a feedback mechanism where the adaptive filter continuously monitors the flow rate signal for noise characteristics and adjusts its filtering parameters accordingly. The filter uses the detected noise frequency and amplitude from the pump-induced disturbances to dynamically modify its transfer function, creating a closed-loop system that maintains valve stability across varying pump speeds.
Solution Approach 2:
The patent employs dynamic filtering that adapts to changing pump speeds by continuously adjusting the filter characteristics to match the current noise frequency. As the pump speed varies, the adaptive filter dynamically recalibrates its parameters to maintain effective noise attenuation, preventing valve oscillations regardless of the operating speed.
3Object-affected harmful factors
If adaptive filters are used to track noise frequency changes, then the noise attenuation effectiveness is improved, but the device complexity increases due to the need for noise reference and cascaded filter structures
Solution Approach 1:
The patent segments the filtering function into multiple cascaded adaptive filters, each handling specific aspects of noise attenuation. The first adaptive filter processes the flow rate signal to generate a noise reference, while the second adaptive filter uses this reference to attenuate the noise. This segmentation allows complex noise patterns to be handled by simpler, specialized filter stages.
Solution Approach 2:
The patent introduces a noise reference signal as an intermediary between the flow rate signal and the final filtered output. The noise reference acts as a mediator that captures the pump-induced noise characteristics, which is then used by the second adaptive filter to selectively attenuate noise while preserving the actual flow rate information.
Data Source
AI summary
An electronics with cascaded adaptive filters for attenuating noise in a feedback path of a flow controller is provided. The electronics includes a signal processor configured to receive a flow signal from a flow sensor, the flow sensor being configured to measure a flow rate of the pulsating flow, generate a noise reference signal from the flow signal and generate a flow rate signal using the noise reference signal. The electronics also includes a controller communicatively coupled to the signal processor, the controller being configured to generate a flow rate control signal using the flow rate signal, and a signal generator communicatively coupled to the controller. The signal generator is configured to receive the flow rate control signal, generate a valve signal based on the flow rate control signal, and provide the valve signal to a valve to control the flow rate of the pulsating flow.