EVSE Capacitor Reforming Using a Mobile Off-Grid Power Source
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Solution Overview
Problem
Electrolytic capacitors in electric vehicle charging stations degrade due to extended unpowered storage, leading to increased leakage currents and potential component failure, necessitating a method to restore their performance before use.
Innovation Solution
A mobile reforming system using an off-grid electric power source, such as a battery or generator, applies a controlled voltage pattern to electrolytic capacitors during commissioning, utilizing AC or DC power electronics to reset their storage life and reduce degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If electrolytic capacitors are stored in unpowered condition for extended periods, then storage convenience is improved, but leakage current increases and component reliability deteriorates
Solution Approach 1:
The system performs preliminary reforming action during commissioning before the capacitors are put into service. This preliminary action restores the oxide layer on the capacitor plates, preventing future degradation and high leakage currents that would occur during extended unpowered storage periods.
Solution Approach 2:
The EVSE controller automatically detects when capacitors have been in unpowered storage and initiates the reforming process without external intervention. The system uses its own power electronics and control algorithms to self-restore the capacitors, eliminating the need for manual testing or external equipment.
2Productivity
If electrolytic capacitors are used in EVSE, then charging functionality is improved, but field failure rate increases due to storage degradation
Solution Approach 1:
The EVSE controller continuously monitors capacitor health parameters and uses feedback from these measurements to determine when reforming is needed. The controller adjusts the reforming voltage and duration based on real-time capacitor condition, optimizing the restoration process and preventing future failures.
Solution Approach 2:
The system changes the electrical parameters (voltage, current, time) of the reforming process based on capacitor degradation state. By dynamically adjusting these parameters, the system effectively restores capacitor performance without causing damage, thereby reducing field failure rates while maintaining charging functionality.
3Duration of action of stationary object
If reforming voltage pattern is applied to electrolytic capacitors, then capacitor life is extended, but device complexity increases
Solution Approach 1:
The EVSE controller and power electronics are designed to perform multiple functions: normal charging operations, capacitor reforming, and health monitoring. By making the controller multi-functional, the system extends capacitor life through reforming without requiring separate dedicated equipment, thus avoiding increased device complexity.
Solution Approach 2:
The control algorithm acts as an intermediary between the power electronics and the capacitors. It manages the complex reforming voltage pattern generation and timing, simplifying the overall system architecture by centralizing control logic rather than requiring complex hardware circuits for voltage pattern generation.
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 method reduces field failure rates, extends capacitor life, and lowers operational costs by minimizing hardware replacements, while enabling quick and efficient capacitor restoration at various locations.
Implementation Method 1
The electrolytic capacitors have a leakage current when a direct current is applied. After long dead storage of the electrolytic capacitors, the electrolytic capacitors may degrade such that this leakage current may increase... Therefore, in case of extended stay in an unpowered condition, the electrolytic capacitors need to be reformed
Data Source
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AI summary
A method for reforming an electrolytic capacitor assembly of an electric vehicle supply equipment, EVSE, configured for connecting to an electric grid for charging an electric vehicle, EV, using electric power from the electric grid, the method including: connecting a mobile off-grid electric power source to the EVSE; and applying to the electrolytic capacitor assembly, by the mobile off-grid electric power source, a reforming voltage pattern for reforming the electrolytic capacitor assembly.