Pulsed Electric Discharge Voltage Feedback for Stable Forming Pressure
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Solution Overview
Problem
In power electronics, pulsed electric discharge devices used in applications like electrohydraulic forming face challenges due to uncontrolled voltage levels at arc creation, leading to inconsistent forming pressures and non-compliant metal parts.
Innovation Solution
A device with a control module that adjusts the heating voltage set point based on estimated energy dissipation and measured breakdown voltage, ensuring consistent energy conversion into pressure waves by calculating a new set point using formulas like Eloss=½×C×(VC2−VB2 and VC=(2Eloss⁄C+VB_CONS2), thereby controlling the voltage level for each shot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a high voltage pulsed electric discharge device is used to heat liquid and create breakdown conditions, then a gas channel and electric arc are formed allowing current to flow between electrodes, but the voltage level at arc creation is not controlled resulting in inconsistent energy conversion to pressure waves
Solution Approach 1:
The patent implements a feedback control system where the actual breakdown voltage is measured and compared to a reference value. Based on this comparison, the heating voltage set point is adjusted for the next discharge cycle. This closed-loop feedback mechanism ensures that the energy converted to pressure waves remains consistent across multiple shots, directly resolving the reliability issue while maintaining the high power output needed for effective electrohydraulic forming.
Solution Approach 2:
The patent dynamically adjusts the heating voltage set point parameter based on the measured breakdown voltage. By changing this key parameter in response to actual process conditions, the system maintains consistent energy conversion to pressure waves. The control module modifies the heating voltage set point using a predetermined adjustment rule when the breakdown voltage deviates from the reference value, ensuring reliable and repeatable forming pressure.
2Temperature
If the heating voltage is increased to ensure breakdown conditions are met, then the liquid heats to boiling point and creates a gas channel, but the energy dissipation varies causing inconsistent forming pressure
Solution Approach 1:
The feedback control system measures the actual breakdown voltage and uses this information to adjust the heating voltage set point for subsequent discharges. This ensures that the liquid is heated to the appropriate temperature to create consistent gas channels and breakdown conditions, while compensating for variations in energy dissipation. The feedback mechanism directly addresses the manufacturing precision issue by maintaining consistent forming pressure across multiple operations.
3Reliability
If a control module is added to measure and adjust heating voltage set point based on breakdown voltage, then consistent energy conversion and forming pressure are achieved, but device complexity increases
Solution Approach 1:
The patent introduces a control module with feedback capability that measures breakdown voltage and adjusts the heating voltage set point accordingly. While this adds some device complexity, it achieves the critical goal of consistent forming pressure. The feedback control system comprises essential components (measurement, comparison, and adjustment) that work together to ensure reliable and repeatable electrohydraulic forming results, making the added complexity justified by the significant improvement in process consistency.
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 approach ensures consistent forming pressure from one test to another, producing compliant metal parts by accurately controlling the energy conversion into pressure waves.
Implementation Method 1
During the heating phase, the voltage defined between both electrodes allows the liquid to be heated to boiling point
Implementation Method 2
the voltage defined between both electrodes allows the liquid to be heated to boiling point in order to create a gas channel
Implementation Method 3
measure the voltage across the electrodes to determine the breakdown voltage at which the pulsed electric discharge occurred
Implementation Method 4
The energy concentrated between the electrodes, which is then converted into a pressure wave
Data Source
AI summary
The present invention concerns a device for pulsed electric discharge in a liquid comprising a control module configured to control a voltage generator such that the voltage generator applies a predetermined heating voltage setpoint between electrodes during a heating period until a pulsed electric discharge is obtained between the electrodes, in order to measure the breakdown voltage during the pulsed electric discharge, in order to estimate the quantity of energy supplied to the liquid during the heating period, referred to as the “quantity of heating energy”, from the predetermined heating voltage setpoint and the measured breakdown voltage, and in order to determine a new heating voltage setpoint to apply between the electrodes of the at least one pair of electrodes at the next pulsed electric discharge based on the estimated quantity of heating energy and a predefined breakdown voltage setpoint.