Solenoid Valve Drive Circuit Using Zero-Cross Inrush Control
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Solution Overview
Problem
Solenoid valve drive control devices face challenges in using commercial AC power supply voltage, leading to noise generation from inrush currents and inefficient energy usage, particularly due to excessive inrush currents to the coil's stray capacity and continuous power consumption after the plunger is attracted.
Innovation Solution
A solenoid valve drive control device that employs a switching device to control current application to the solenoid, utilizing zero cross timing to start current flow and incorporating a snubber circuit for energy discharge, thereby reducing inrush currents and optimizing holding current levels to conserve energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If commercial AC power supply voltage is used to drive the solenoid valve, then the valve can operate with standard power supply, but inrush currents generate noise and electromagnetic interference exceeding EMC standards
Solution Approach 1:
The patent applies periodic pulsed action by controlling the solenoid coil with alternating current cycles - applying current to attract the plunger, then interrupting current while maintaining position through mechanical retention. This periodic on-off operation reduces continuous inrush currents and associated EMI while maintaining valve functionality with standard AC power supply.
Solution Approach 2:
The patent implements preliminary action by pre-attracting the plunger to the core before full operation, and using a retention mechanism to maintain position during current interruption. This preliminary mechanical engagement allows current to be reduced or interrupted without losing valve position, thereby reducing inrush currents and EMI.
2Reliability
If continuous current is applied to the solenoid to maintain plunger attraction, then the valve remains reliably open, but energy consumption increases unnecessarily
Solution Approach 1:
The patent employs periodic action by applying current only during the attraction phase and then interrupting it while maintaining plunger position through mechanical retention. This allows the valve to remain reliably open without continuous power consumption, achieving both reliability and energy efficiency.
Solution Approach 2:
The patent implements self-service by using the mechanical system (plunger-core attachment and retention mechanism) to maintain valve position without continuous electrical power. The mechanical retention structure sustains the open state autonomously after initial electrical attraction, eliminating the need for continuous energy input.
3Speed
If high current is applied to the solenoid coil to ensure rapid plunger attraction, then the valve opens quickly, but inrush current to the coil's stray capacity generates excessive noise
Solution Approach 1:
The patent applies periodic action by delivering high current in controlled pulses only during the necessary attraction phase, then rapidly interrupting it. This pulsed approach maintains fast plunger attraction speed while minimizing the duration of inrush current, thereby reducing noise and EMI from the coil's stray capacity.
Solution Approach 2:
The patent implements skipping by rapidly completing the attraction process with high current and then quickly transitioning to the retention phase with reduced or interrupted current. This rushes through the high-inrush-current phase as quickly as possible, minimizing noise generation while achieving rapid valve opening.
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 solution effectively controls noise generation from inrush currents, meets EMC standards, and achieves energy conservation by managing inrush currents and holding power efficiently, allowing the solenoid valve to operate reliably with commercial AC power supply voltage.
Implementation Method 1
by applying an electric current to the electromagnetic coil 208, the plunger 236 is moved in the directions of the attracting member 224 against the urging spring 240
Implementation Method 2
the alternating current from the AC power supply is converted into direct current by using the full-wave rectification
Data Source
AI summary
(Problem)The invention is to provide to a solenoid valve drive control device, in which though the magnetic path is normally composed (i.e. the plunger is attached to the attracting member), it is never determined by mistake as the dropout, and it is never entered into the reabsorption mode of the plunger.(Resolution Approach)The invention is a solenoid valve drive control device of the invention, in which by controlling of the zero cross timing generation device 72, after application of the electric current to the solenoid 66 is started at zero cross timing by the switching device 68, when the current value that flows to the solenoid 66 detected by the electric current sensing device 78 reaches the circuit protection electric current value Ic (αA), a stabilization mode that repeats the ON-OFF cycle plural times (four times of the total in the Embodiment of FIG. 4), in which application of the electric current to the solenoid 66 is interrupted by the switching means 84, is operated (see A5-A8 in FIG. 4).