Bi-directional MOSFET Switch for Redundant Power Sources
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Solution Overview
Problem
Redundant power systems face challenges in seamlessly transitioning power from a primary source to a secondary source and managing charging and discharging operations efficiently, particularly in ensuring uninterrupted power supply and protecting against faults.
Innovation Solution
A bi-directional switch system utilizing MOSFETs controlled by a controller to operate in saturation and linear regions, enabling efficient power transfer, charging, and disconnection, with voltage and current controllers regulating transitions and fault management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an active battery converter is used for power transition and charging, then reliable power supply is ensured, but system cost and complexity increase
Solution Approach 1:
The patent extracts the complex active battery converter from the system and replaces it with a simpler bi-directional switch circuit using MOSFETs. The essential function of power transition and charging is preserved while removing the complicated converter infrastructure, thereby reducing system cost and complexity while maintaining reliability.
Solution Approach 2:
The patent employs inexpensive MOSFET switches instead of expensive active battery converters. The MOSFETs are simple, cost-effective components that can be easily replaced if needed, providing a economical solution that maintains system functionality without requiring complex expensive equipment.
2Productivity
If MOSFETs operate in saturation region for power discharge, then efficient power transfer is achieved, but charging current control becomes challenging
Solution Approach 1:
The patent dynamically switches MOSFETs between saturation and linear regions based on operational requirements. During power discharge, MOSFETs operate in saturation for high efficiency. During charging, they transition to linear region for precise current control. This dynamic operation mode switching resolves the contradiction between efficiency and controllability.
Solution Approach 2:
The patent changes the operational parameters of MOSFETs by adjusting their region of operation (saturation vs. linear) based on the charging/discharging state. This parameter change enables the system to optimize for either power transfer efficiency or current control depending on the operational phase, resolving the inherent contradiction between these two requirements.
3Reliability
If the secondary power source remains connected to the power bus, then continuous power availability is maintained, but fault damage risk increases
Solution Approach 1:
The patent implements preliminary protective action by incorporating fault detection circuitry that monitors the power bus condition. When a fault is detected, the system proactively disconnects the secondary power source before damage can occur, preventing harmful effects while maintaining normal operation during healthy conditions.
Solution Approach 2:
The patent introduces a bi-directional switch as an intermediary component between the secondary power source and the power bus. This intermediary enables the system to maintain connection for power availability while providing a controlled disconnection path when faults occur, thus mediating between the conflicting requirements of continuous availability and fault 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
Facilitates seamless power transitions, efficient charging and discharging, and fault protection, ensuring uninterrupted power supply while minimizing damage to the secondary power source.
Implementation Method 1
control signals to the first gate and the second gate that cause the first and second MOSFETs to operate in saturation regions during a first operational state to cause the first power source to discharge
Implementation Method 2
the first MOSFET operates in a linear region during a second operational state to limit a charging current that charges the first power source
Data Source
AI summary
Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for controlling a battery power source. In one aspect, a system includes a first MOSFET having a first gate, a first source, and a first drain. A second MOSFET having a second gate, a second source, and a second drain. The first source is connected to the second source, and the second drain is coupled to a ground. A control circuit connected to the first gate and the second gate and that provides control signals to the first gate and the second gate that cause the first and second MOSFETS to operate in saturation regions during a first operational state to cause the first power source to discharge and the first MOSFET operates in a linear region during a second operational state to limit a charging current that charges the first power source.