Stepwise Battery Module Precharge for Inrush Current Control
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Solution Overview
Problem
High voltage direct current systems with large capacitive loads experience excessive inrush current during initial power-up, leading to stress and potential damage to components, and post-discharge processes are inefficient in managing application bus voltage during shutdown, resulting in deleterious effects.
Innovation Solution
A bypassable battery module system that activates and bypasses battery modules in a stepwise manner to precharge and post-discharge an application bus, reducing the voltage difference and inrush current, thereby minimizing ohmic heating and power loss, and allowing for smaller, less costly precharge circuitry components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional precharge circuitry is used to limit inrush current, then component stress is reduced, but the precharge circuitry becomes larger and more costly
Solution Approach 1:
The battery system is divided into multiple modular battery packs that can be independently activated. During precharge, the controller enables battery packs in a stepwise manner rather than all at once, segmenting the inrush current limitation process into discrete stages. This eliminates the need for large, expensive traditional precharge circuitry while still protecting components from stress.
2Speed
If all battery packs are activated simultaneously during power-up, then system startup is faster, but excessive inrush current damages components
Solution Approach 1:
The controller performs preliminary assessment of battery pack states before full activation. It identifies which battery packs are ready and enables them in a controlled sequence, performing the necessary current limitation action in advance of full system activation. This allows fast startup while preventing inrush current damage through pre-planned sequential enabling.
3Productivity
If application bus voltage is discharged quickly during shutdown, then energy recovery is faster, but high voltage stress damages components
Solution Approach 1:
The controller implements periodic action by discharging the application bus voltage in controlled intervals rather than continuously. It enables battery packs in sequence during shutdown, allowing the bus to discharge through each enabled pack over time. This periodic discharge approach recovers energy efficiently while limiting voltage stress on components through the stepped process.
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 stepwise activation and bypassing of battery modules in the bypassable battery module system effectively reduce inrush current, minimize power loss due to ohmic heating, and prevent damage to system components, while enabling smaller and less expensive precharge circuitry, thus enhancing the efficiency and reliability of precharge and post-discharge operations.
Implementation Method 1
A bypassable battery module system that activates and bypasses battery modules in a stepwise manner to precharge and post-discharge an application bus
Implementation Method 2
reducing the voltage difference and inrush current, thereby minimizing ohmic heating and power loss
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A method may include activating two or more bypassable battery modules in succession through a current-limiting circuit to precharge an application bus from a power source.