Sensorless Valve Control Using Back-EMF Timing Correction
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Solution Overview
Problem
Existing electric solenoids in valve control systems suffer from errors in opening and closing times due to variations in pressure, temperature, maintenance, contamination, and fluid viscosity, leading to inaccurate duty cycle control, especially at high PWM frequencies, and external sensors increase cost and complexity without addressing these issues.
Innovation Solution
A sensorless adaptive valve control system that uses internal detection and correction of the effective duty cycle by analyzing back electromotive force (BEMF) peaks to adjust control voltage timing, compensating for errors in opening and closing times through an adaptive control algorithm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external sensors are mounted to the solenoid for detecting attributes, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The solenoid system performs self-diagnostics by monitoring its own electrical characteristics (current, voltage, impedance) to detect mechanical faults and performance degradation. The control circuit analyzes back-EMF signals and current profiles to identify issues such as stuck valves, contaminated fluids, or worn components without requiring external sensors.
Solution Approach 2:
The patent replaces mechanical sensing systems with electrical field-based detection. By measuring electrical parameters (current, voltage, impedance, back-EMF) of the solenoid coil, the system infers mechanical state of the valve without physical contact or external mechanical sensors.
2Measurement precision
If external sensors are used for monitoring, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The solenoid system performs self-diagnostics by monitoring its own electrical characteristics (current, voltage, impedance) to detect mechanical faults and performance degradation. The control circuit analyzes back-EMF signals and current profiles to identify issues such as stuck valves, contaminated fluids, or worn components without requiring external sensors.
3Ease of operation
If feedforward control is used for valve actuation, then ease of operation is improved, but manufacturing precision deteriorates due to timing errors
Solution Approach 1:
The control circuit continuously monitors the solenoid's electrical characteristics and compares actual valve response against expected performance. When timing deviations are detected (such as delayed opening or closing), the system adjusts PWM duty cycle and timing parameters in real-time to compensate for drift caused by environmental changes, fluid viscosity variations, or component aging.
Solution Approach 2:
The control system dynamically adjusts operating parameters (PWM frequency, duty cycle, voltage levels) based on real-time feedback from electrical measurements. This allows the system to adapt to changing conditions such as temperature variations, fluid contamination, or mechanical wear, maintaining precise timing control without requiring mechanical adjustments.
4Manufacturing precision
If initial calibration is performed during manufacturing, then manufacturing precision is improved, but adaptability deteriorates when operating conditions change
Solution Approach 1:
The control circuit continuously monitors the solenoid's electrical characteristics and compares actual valve response against expected performance. When timing deviations are detected (such as delayed opening or closing), the system adjusts PWM duty cycle and timing parameters in real-time to compensate for drift caused by environmental changes, fluid viscosity variations, or component aging.
Solution Approach 2:
The system dynamically changes electrical operating parameters (voltage, current, PWM frequency, duty cycle) based on real-time feedback from electrical measurements. This allows adaptation to different operating conditions such as temperature changes, fluid contamination, or mechanical wear without requiring mechanical reconfiguration.
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
The system provides precise and accurate valve actuation by continuously calibrating to environmental and operational changes, maintaining high timing accuracy despite variations in conditions, without the need for external sensors, thus reducing costs and complexity.
Implementation Method 1
a solenoid 102 including a coil 108 and a movable mechanism
Implementation Method 2
such that a back electromotive force (BEMF) peak is created within the coil based on the movable mechanism being moved
Data Source
Figure 1~2
Figure 3A
Figure 3B
AI summary
A valve control system and method can include: a control logic configured to couple to a conductor and to a movable mechanism such that a back electromotive force (BEMF) peak is created within the conductor based on the movable mechanism being moved, the control logic further configured to: apply a control voltage to the conductor; detect the BEMF peak; determine a peak timing for the BEMF peak, and adjust a control voltage timing for the control voltage based on the peak timing.