Regenerative Solenoid Drive Circuit for Pull-In and Hold Switching
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Solution Overview
Problem
Solenoid drive circuits in aerospace applications face inefficiencies due to continuous operation in 'pull-in' mode, leading to excessive power waste, as they lack a hardware-based solution for switching between 'pull-in' and 'hold' modes efficiently, relying on software monitoring which adds overhead.
Innovation Solution
A solenoid drive circuit with a regenerative drive circuit including a diode bridge and capacitors that allows for efficient switching between 'pull-in' and 'hold' modes by storing energy in capacitors and regulating current, enabling lower input voltage usage and energy recapture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If full rated voltage is applied continuously to energize the solenoid, then the solenoid remains reliably engaged, but power dissipation in the drive circuit and solenoid increases excessively
Solution Approach 1:
The patent applies periodic voltage control by switching between full rated voltage during pull-in mode and reduced voltage during hold mode. This periodic action maintains solenoid engagement reliability while significantly reducing average power dissipation in both the drive circuit and solenoid coil.
Solution Approach 2:
The patent dynamically adjusts the voltage applied to the solenoid based on operational state. During pull-in, full voltage is applied to ensure reliable engagement; during hold, reduced voltage is sufficient to maintain engagement. This dynamic voltage adjustment resolves the contradiction between reliability and energy consumption.
2Reliability
If full rated voltage is applied to pull-in the solenoid, then the solenoid engages reliably, but excessive current causes increased power dissipation and potential damage
Solution Approach 1:
The regenerative capacitor is pre-charged to the rated voltage before pull-in operation. During pull-in mode, this pre-charged capacitor provides additional voltage in series with the power source, ensuring reliable solenoid engagement without requiring continuously high power dissipation from the main power source.
Solution Approach 2:
The patent converts the energy that would normally be dissipated as heat during solenoid operation into useful energy by capturing it in the regenerative capacitor during hold mode. This captured energy is then reused during pull-in mode, transforming what would be wasted energy into a beneficial resource that reduces overall power dissipation.
3Use of energy by moving object
If reduced voltage is applied to hold the solenoid, then power dissipation decreases, but the solenoid may not maintain reliable engagement
Solution Approach 1:
The regenerative capacitor acts as an intermediary energy storage device that bridges the power source and solenoid. During hold mode, it maintains the voltage necessary for reliable engagement while allowing the power source to operate at lower power levels, thus maintaining reliability while reducing overall power dissipation.
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
This solution reduces power consumption by regulating pull-in and hold currents with lower input voltage, recapturing energy for reuse, and reducing overvoltage stress on switches, enhancing efficiency and power management in solenoid operations.
Implementation Method 1
a first regenerative drive circuit connected to the first solenoid control circuit and that includes a first regenerative capacitor
Implementation Method 2
a first diode bridge formed of four diodes (D1, D2, D3 and D4) and that has a positive input, a negative input, a positive output and a negative output
Implementation Method 3
an electromagnetically inductive coil wound around a moveable steel or iron slug called the armature or plunger
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A solenoid drive circuit (202) includes a power source (V1), a first solenoid control circuit (206) connected to the power source, the first solenoid control circuit including a first solenoid coil (L1) and a first solenoid control switch (S1) that controls a flow current through the first solenoid coil and a first regenerative drive circuit (204) connected to the first solenoid control circuit and that includes a first regenerative capacitor (C1). The first regenerative drive circuit can include a first diode bridge formed of four diodes (D1, D2, D3 and D4) and that has a positive input, a negative input, a positive output and a negative output, wherein the first regenerative capacitor is connected between the positive and negative inputs.