Battery Current-Limiting Circuit for Inrush and Outrush Control
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Solution Overview
Problem
Current battery technologies face issues with high inrush and outrush currents, which can cause system failures, damage to components, and reduced performance due to the lack of effective current limiting mechanisms, especially in electric vehicles with high-voltage batteries and capacitive loads.
Innovation Solution
The implementation of a circuit apparatus comprising a battery, a resistive load, a switch (implemented as MOSFETs), a resistor, an inductor, and a control circuit that regulates the switch based on voltage across the resistor to control current flow, effectively limiting inrush and outrush currents by interrupting or allowing current flow based on predetermined voltage thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If no current limiting mechanism is used, then power delivery speed is improved, but system reliability deteriorates due to high inrush and outrush currents causing failures and damage
Solution Approach 1:
The circuit performs preliminary action by pre-charging capacitive loads through the resistor before main power connection, and by having the switch already in place to quickly interrupt outrush currents. This preparatory measure prevents harmful inrush currents from damaging the system while maintaining fast power delivery when needed.
Solution Approach 2:
The resistor serves as an intermediary element that temporarily limits inrush current during capacitor charging. The switch acts as an intermediary that可以快速 interrupt outrush currents. These intermediary components protect the system without significantly impacting normal power delivery performance.
2Object-affected harmful factors
If a current limiting resistor is used, then inrush current is reduced, but power loss increases due to resistive heating
Solution Approach 1:
The circuit uses periodic action by temporarily engaging the resistor only during the brief inrush current phase, then disconnecting it through the switch once capacitors are charged. This allows the resistor to perform its current-limiting function only when necessary, minimizing continuous power loss while still protecting against inrush currents.
Solution Approach 2:
The resistor performs preliminary current limiting only during the initial charging phase, after which the switch disconnects it from the circuit. This preliminary action prevents inrush damage without causing continuous energy loss during normal operation.
3Measurement precision
If a complex control system is implemented, then current control precision is improved, but device complexity increases
Solution Approach 1:
The circuit employs self-service by using the inherent voltage drop across the resistor during inrush current to automatically trigger the switch through voltage detection. This self-activating mechanism provides precise current control without requiring external complex control systems, microcontrollers, or additional sensing circuitry.
Solution Approach 2:
The circuit implements simple feedback by monitoring the voltage across the resistor and using it to control the switch state. This feedback mechanism automatically adjusts current flow based on real-time conditions, providing precise control with minimal complexity.
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 solution effectively reduces high inrush and outrush currents, preventing system failures and damage, while maintaining performance by ensuring safe and controlled current flow during battery discharge and charge cycles, even when multiple batteries are connected to a single load.
Implementation Method 1
an inductor electrically coupled in series with the precharge resistor. The inductor may limit the amount of current that can flow to or from the battery at any given time
Implementation Method 2
a precharge resistor electrically coupled in series with the inductor. In an embodiment, the precharge resistor may be used to precharge capacitive loads
Data Source
AI summary
In general, one aspect disclosed features an apparatus, comprising: a battery; a resistive load; a switch comprising a first transistor and a second transistor; a resistor; an inductor; and a control circuit; wherein the switch, the resistor, and the inductor are coupled in series between the battery and the resistive load; and wherein the control circuit controls the switch based on a voltage across the resistor. In general, another aspect disclosed features an apparatus, comprising: a battery; a resistive load; a switch; a resistor; an inductor; and a control circuit; wherein the switch, the resistor, and the inductor are coupled in series between the battery and the resistive load; and wherein the control circuit controls the switch based on a voltage across the resistor.