EV Recharge Bias Circuit for Stable Series-Mode Initialization
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Solution Overview
Problem
Indeterminate conditions during electric vehicle recharge initialization can cause interface issues with off-board chargers and on-board diagnostics due to low or unsteady voltages, leading to potential damage and inefficiencies.
Innovation Solution
A reconfigurable energy storage system with a diode and bias circuit that maintains a reverse bias across the diode during series mode, using a network of resistances to limit voltage and current, and switches to manage parallel and series configurations, ensuring stable charging and discharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If power rectifiers are used to couple battery modules in series during recharging initialization, then the system can enable series mode for charging, but indeterminate voltage conditions occur before the charger is fully connected causing interface issues
Solution Approach 1:
The bias circuit is activated before the off-board charger is fully connected to establish predetermined voltage levels across the diode. This preliminary action ensures that when the charger connects, the interface voltages are already stabilized, preventing indeterminate conditions and ensuring reliable communication and control signals are generated immediately
2Power
If battery modules are coupled in series during recharging, then charging voltage is increased, but low or unsteady voltages occur at the charge interface during initialization
Solution Approach 1:
The bias circuit acts as an intermediary between the battery modules and the off-board charger during initialization. It provides a stable voltage reference that mediates the transition from disconnected to connected state, ensuring that the high voltage series configuration maintains stable interface voltages even before full charging power is applied
3Productivity
If the diode is used to convey charging power between submodules, then power transfer efficiency is improved, but the diode may be damaged by reverse current during parallel mode
Solution Approach 1:
The bias circuit maintains a reverse bias across the diode during series mode initialization, which prevents reverse current from damaging the diode. This preliminary protective action ensures the diode is already in a protected state before charging begins, allowing efficient power transfer without risking component damage from reverse polarity conditions
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
Stabilizes charging by maintaining a reverse bias during indeterminate conditions, preventing damage and ensuring efficient energy transfer between battery submodules, thus enhancing charging safety and efficiency.
Implementation Method 1
The diode is operable to convey the charging power between the first submodule and the second submodule while the reconfigurable energy storage system is in the series mode and the charging power is present
Implementation Method 2
The bias circuit is directly connected to the diode, and operable to maintain a reverse bias across the diode while the reconfigurable energy storage system is in the series mode and the charging power is absent
Data Source
AI summary
An electric vehicle includes a reconfigurable energy storage system with a first submodule and a second submodule. An interface circuit is operable to transfer a charging power to the reconfigurable energy storage system from a charging station that is external to the electric vehicle. A switching circuit is operable to electrically arrange the first submodule and the second submodule in series or in parallel. A diode is operable to convey the charging power between the first submodule and the second submodule while the reconfigurable energy storage system is arranged in series and the charging power is present. A bias circuit is operable to maintain a reverse bias across the diode while the reconfigurable energy storage system is arranged in series and the charging power is absent.