Mass Flow Controller Linearization for Stable Valve Response
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Solution Overview
Problem
Current Mass Flow Controllers (MFCs) lack the sophistication to maintain precise and continuous control of fluid flow rates without introducing noise due to non-linear artifacts, which affects their performance across varying operating conditions.
Innovation Solution
The implementation of a Gain-Lead-Lag (GLL) controller algorithm within the MFC, combined with real-time fluid modeling and valve modeling, allows for precise linear response control by filtering set point values and dynamically adjusting the drive signal based on actual pressure, temperature, and flow rate, eliminating non-linear transient responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional MFC control methods are used, then the device structure remains simple, but the flow rate control precision deteriorates and non-linear artifacts are introduced
Solution Approach 1:
The patent applies parameter changes by implementing a Gain-Lead-Lag (GLL) controller algorithm that dynamically adjusts control parameters (gain, lead, lag) based on real-time operating conditions. This allows the MFC to maintain precise flow rate control across varying pressures and temperatures by continuously optimizing controller parameters, thereby resolving the contradiction between control precision and device complexity.
Solution Approach 2:
The patent employs feedback mechanisms through real-time measurement of pressure, temperature, and flow rate, which are fed back to the GLL controller algorithm. This closed-loop feedback system enables continuous correction of flow rate deviations and eliminates non-linear artifacts, achieving high precision control without requiring overly complex hardware modifications.
2Adaptability or versatility
If the MFC operates across varying operating conditions, then the adaptability improves, but the non-linear artifacts increase and control precision deteriorates
Solution Approach 1:
The patent applies dynamics by implementing a dynamic controller algorithm that continuously adapts to changing operating conditions. The GLL controller dynamically adjusts its parameters based on real-time pressure, temperature, and flow rate measurements, enabling the MFC to maintain precise control across a wide range of operating conditions without introducing non-linear artifacts, thus resolving the contradiction between adaptability and measurement precision.
Solution Approach 2:
The patent changes control parameters dynamically based on operating conditions. The GLL algorithm modifies gain, lead, and lag parameters in real-time according to the current operating state, allowing the system to adapt to varying conditions while maintaining measurement precision and eliminating non-linear artifacts.
3Productivity
If the response time is reduced for faster control, then the productivity improves, but the transient response stability deteriorates
Solution Approach 1:
The patent applies periodic action through the lead-lag compensator in the GLL controller, which introduces controlled phase shifts and time delays to stabilize transient responses. The lead component provides phase advance for faster response, while the lag component provides phase compensation for stability, enabling the system to achieve both fast response time and transient stability simultaneously.
Solution Approach 2:
The patent changes controller parameters dynamically based on the current operating state and transient conditions. The GLL algorithm adjusts gain, lead, and lag parameters in real-time to optimize both response speed and stability, allowing the system to achieve fast transient response without sacrificing stability during flow rate changes.
Data Source
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Figure 3A~3B
AI summary
A mass flow controller that includes a linearization system to control the linear response of a valve in order to control the gain of the mass flow controller. The linearization system includes a flow modeling system for processing at least one of a fluid type, a flow rate, a pressure, and a temperature value signal relating to flow of the fluid through a flow path and determining fluid properties. The linearization system also includes a valve modeling system to determine the required operational characteristics of the valve according to valve specifications, a desired flow rate, and the determined fluid properties. The linearization system determines a gain to control the lift of the valve in order to acquire a desired fluid flow rate. The gain is determined by calculating the derivative of predicted lift with respect to fluid flow and the derivative of drive with respect to predicted lift.