Electromagnetic Dispenser Driver Circuit for Boosted Solenoid Actuation
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Solution Overview
Problem
Existing electric systems face challenges in driving inductive loads that require higher supply voltages than what is available, leading to inefficient charging and potential under or overcharging of energy storage devices, which can prevent solenoids from operating correctly.
Innovation Solution
A method and circuit that charge a capacitor to a predetermined voltage level greater than the supply voltage, using a first switch to induce current in the inductive load, and then discharge the capacitor through a third switch to provide a high voltage current pulse sufficient to actuate mechanical valves, eliminating the need for additional sensing elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a microcontroller monitors a sensing element to determine whether the energy storage device is sufficiently charged, then the charging status can be accurately determined, but a separate sensing device in the form of a precision shunt resistor is required
Solution Approach 1:
The patent merges the sensing function into the existing capacitor structure by detecting voltage across the capacitor terminals. The capacitor serves dual purposes: energy storage and sensing element, eliminating the need for a separate precision shunt resistor. The microcontroller measures voltage directly at the capacitor terminals, combining storage and sensing functions in one component.
2Ease of operation
If charging cycles are repeated a predetermined number of times, then the charging process is simple to control, but there is a risk that the energy storage device is charged more than necessary or not sufficiently charged
Solution Approach 1:
The patent implements feedback control by continuously monitoring the voltage across the capacitor terminals during charging. The microcontroller reads the voltage signal and compares it against a predetermined threshold voltage. When the threshold is reached, the charging process is automatically terminated. This closed-loop feedback mechanism ensures reliable charging completion without requiring predetermined cycle counts, adapting to actual charging needs.
3Power
If the capacitor is charged to a predetermined voltage level greater than the supply voltage, then sufficient current pulse can be provided to actuate the solenoid valve, but the charging process becomes more complex
Solution Approach 1:
The patent applies preliminary action by pre-charging the capacitor to a voltage level higher than the supply voltage during a charging phase before the solenoid actuation is needed. The capacitor is charged through a charging switch and current limit resistor to accumulate sufficient energy. When actuation is required, the stored energy is rapidly discharged through the solenoid via a discharge switch, generating the high current pulse needed for reliable valve opening without requiring complex real-time power conversion during actuation.
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
Enables the actuation of solenoid valves in dishwashers by providing a high current pulse necessary for detergent and rinse aid dispensing, while minimizing power consumption and avoiding overcharging, without requiring separate sensing devices.
Implementation Method 1
a capacitor (C) connected to the inductive load and the first switch, wherein the capacitor is charged by the supply voltage via the inductive load
Implementation Method 2
the inductive load, wherein closing of the first switch causes a current sufficient for actuating a mechanical valve associated with the inductive load to be induced in the inductive load
Data Source
AI summary
A circuit for driving an inductive load may include an input, an output, a first switch, and at least one capacitor. The first switch may cause the capacitor to be charged by the supply voltage via the inductive load. A device may discontinue the charging of the capacitor when the voltage has reached a predetermined level greater than that of the supply voltage. A first and a second diode may prevent the capacitor from discharging via the first switch and blocking inductive load current from entering the power supply, respectively. A second switch and the capacitor may be connected to the third switch to cause discharging of the capacitor via the third switch into the inductive load. Closing of the first switch may cause a current sufficient for actuating a mechanical valve to be induced in the inductive load.