Active Battery Balancing Circuit Using Bi-Directional DC-AC Converters
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Solution Overview
Problem
Passive battery balancing systems result in energy loss due to heat dissipation in resistors, requiring large space and becoming impractical as cell capacity increases, while existing active systems face high installation costs and space requirements.
Innovation Solution
An active battery balancing circuit utilizing bi-directional DC-AC voltage converters and an AC balancing bus, with a control microprocessor and planar transformers, to efficiently transfer charge between cells without heat dissipation, using a monitoring system and switch matrix to manage charge distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If passive battery balancing circuits are used, then charge balancing between cells is achieved, but energy is lost as heat and large space is required
Solution Approach 1:
The patent replaces the passive mechanical resistor-based balancing system with an active electronic system using DC-AC voltage converters and planar transformers. This substitution enables energy to be transferred between cells through electromagnetic conversion rather than being dissipated as heat, thereby reducing energy loss while maintaining compact dimensions through high-frequency switching operation
Solution Approach 2:
The patent changes the operating parameters by using high-frequency AC switching in the voltage converters rather than continuous DC current through resistors. This parameter change allows for much smaller component sizes (planar transformers, capacitors, inductors) while improving energy efficiency through reversible energy conversion instead of irreversible heat dissipation
2Measurement precision
If individual DC/AC converters are provided for each cell, then precise charge balancing is achieved, but installation costs and space requirements increase
Solution Approach 1:
The patent merges multiple individual cell balancing functions into a single centralized DC-AC voltage converter that serves all battery cells. This converter connects to a common AC balancing bus, allowing one converter to balance charges across multiple cells by transferring energy between them, thereby reducing installation complexity and cost while maintaining precise balancing capability through individual cell monitoring and controlled energy transfer
Solution Approach 2:
The single DC-AC voltage converter is designed with universal functionality to handle charge balancing for multiple battery cells simultaneously. It can convert DC from any cell to AC on the balancing bus and vice versa, making it a multi-functional device that replaces what would otherwise require multiple dedicated converters, thus reducing overall system 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 reduces energy loss, minimizes space requirements, and lowers costs by efficiently balancing cell charges during charging and discharging, extending battery life and reducing charging time.
Implementation Method 1
bi-directional voltage converters connected to each battery unit for converting DC to AC in a first direction, and vice versa in the opposite direction
Data Source
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AI summary
The invention relates to an active battery balancing circuit comprising: a first battery unit; at least one further battery unit; separate bi-directional DC-AC voltage convertors connected to each battery unit for converting DC to AC in a first direction, and vice versa in the opposite direction;an AC balancing bus connecting each voltage convertor and a control microprocessor; wherein said balancing circuit is configured to a) provide excess DC current flow from a battery unit to one of said bidirectional voltage convertors; b) convert said excess DC current to AC current and provide this to said AC balancing bus; c) provide said excess AC current in said AC balancing bus to one of said bidirectional voltage convertors; d)convert said excess AC current to DC current using said bi-directional voltage convertor and return said converted DC current to a battery unit that requires additional charge.