Solid-State Current Limiter Circuit for Battery Inrush Control
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Solution Overview
Problem
Inrush current surges in high capacitive loads can cause damage and system failures in power distribution systems, particularly in aircraft applications, due to the risk of bus voltage drops, electromagnetic interference, and cable degradation, which existing solutions like pre-charge resistors and electromechanical relays increase physical volume, weight, and cost while impacting reliability.
Innovation Solution
A multi-functional current limiter system using solid-state bi-directional switches and a damping RL circuit, which can limit arc/surge current, provide fast response, initial pre-charge, and mitigate voltage imbalances, replacing conventional fuse devices and allowing for integration with energy storage devices to control inrush currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pre-charge resistors and electromechanical relays are used to limit inrush current, then inrush current is limited and system protection is improved, but physical volume, weight, and cost increase while reliability decreases
Solution Approach 1:
The patent replaces electromechanical relays with solid-state power controllers (SSPCs) that use semiconductor devices to achieve current limiting and switching functions. This substitution eliminates mechanical moving parts, reducing physical volume and weight while improving reliability through faster response times and no arcing issues.
Solution Approach 2:
The SSPC integrates multiple functions including current limiting, pre-charging, fault detection, and protection into a single device. This multi-functionality reduces the need for separate components like pre-charge resistors and relays, thereby reducing overall physical volume and system complexity while maintaining comprehensive system protection.
2Reliability
If pre-charge resistors and electromechanical relays are used to limit inrush current, then inrush current is limited and system protection is improved, but physical volume, weight, and cost increase while reliability decreases
Solution Approach 1:
The patent replaces electromechanical relays with solid-state power controllers (SSPCs) that use semiconductor devices to achieve current limiting and switching functions. This substitution eliminates mechanical moving parts, reducing physical volume and weight while improving reliability through faster response times and no arcing issues.
3Reliability
If pre-charge resistors and electromechanical relays are used to limit inrush current, then inrush current is limited and system protection is improved, but physical volume, weight, and cost increase while reliability decreases
Solution Approach 1:
The SSPC integrates multiple functions including current limiting, pre-charging, fault detection, and protection into a single device. This multi-functionality reduces the need for separate components like pre-charge resistors and relays, thereby reducing overall physical volume and system complexity while maintaining comprehensive system protection.
Solution Approach 2:
The patent combines the functions of pre-charge resistors, electromechanical relays, and protection devices into a single integrated SSPC. This merging of functions reduces the total component count, lowering material costs, assembly costs, and maintenance costs while improving system reliability.
4Temperature
If active temperature control using thermal model is used to limit inrush current, then inrush current is limited and overheating is prevented, but system complexity increases
Solution Approach 1:
The patent uses solid-state power controllers with inherent thermal management capabilities through semiconductor devices. The SSPC can detect thermal conditions and control current flow to prevent overheating without requiring complex active temperature control systems, thus maintaining lower system complexity while achieving effective thermal protection.
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 solution effectively limits inrush currents, reduces the risk of system faults, and enhances reliability by providing fast response and protection against short circuits and voltage imbalances, while reducing physical and cost burdens in power distribution systems.
Implementation Method 1
A first transistor in series with a first diode, wherein a first anode of the first diode is coupled to a first drain of the first transistor, and wherein a first source of the first transistor is coupled to a first node
Implementation Method 2
a first resistor inductor (RL) circuit, wherein the first RL circuit, the first circuit, and the second circuit are arranged in parallel
Implementation Method 3
a first resistor inductor (RL) circuit, wherein the first RL circuit, the first circuit, and the second circuit are arranged in parallel
Implementation Method 4
a second circuit comprising a second transistor in series with a second diode, wherein a second cathode of the second diode is coupled to a second source of the second transistor, and wherein a second drain of the second transistor is coupled to the first node
Data Source
AI summary
Systems for a current limiting circuit are provided. Aspects include a first set of batteries coupled to a battery terminal, a power converter coupled to a power converter terminal, wherein the battery terminal is coupled to the power converter terminal, a first current limiting circuit in series with the first set of batteries, wherein the current limiting circuit comprises a first circuit comprising a first transistor in series with a first diode, a second circuit comprising a second transistor in series with a second diode, a first RL circuit, wherein the first RL circuit, the first circuit, and the second circuit are arranged in parallel, a controller configured to operate the first current limiter in a plurality of modes including a battery discharge mode including the controller operating the first transistor in an off state, and operating the second transistor in a switching state.