Isolation Transformer Voltage Balancing for Series-Connected Storage Cells
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing voltage balancing circuits for series-connected storage cells face issues with wiring congestion, increased cost, and noise generation due to the use of multi-winding flyback transformers, and they cannot perform voltage balancing during storage or when charging/discharging is not occurring.
Innovation Solution
The proposed solution involves using isolation transformers with primary and secondary windings connected in parallel, a rectifying circuit, and a voltage balancing circuit that generates alternating current by switching a direct-current power source, reducing the number of wirings and wire diameter, and incorporating a balance detection circuit to control switching based on voltage differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multi-winding flyback transformer is used for voltage balancing, then voltage equalization can be achieved, but wiring congestion and increased cost occur due to the large number of individual wirings required
Solution Approach 1:
The patent merges multiple secondary windings into a single secondary winding structure. Instead of having multiple isolated secondary windings L21-L2n each requiring individual wirings to cell modules M1-Mn, the invention uses one secondary winding that serves all cell modules through a single common wiring path, dramatically reducing wiring complexity while maintaining voltage balancing functionality
Solution Approach 2:
The single secondary winding is designed to serve multiple functions simultaneously - it provides magnetic coupling to all cell modules M1-Mn and enables voltage balancing across all modules through a unified structure. The secondary winding acts as a universal interface that replaces multiple dedicated windings, reducing both wiring count and system complexity
2Power
If a multi-winding flyback transformer with magnetic gap is used, then required inductance can be obtained, but noise generation increases due to large leakage flux from the magnetic gap
Solution Approach 1:
The invention extracts and eliminates the magnetic gap from the transformer core structure. By removing the magnetic gap that causes large leakage flux, the patent eliminates the primary source of electromagnetic noise while preserving the required inductance through alternative core design, thereby reducing noise generation without sacrificing power characteristics
3Loss of energy
If voltage balancing is performed only when necessary and stopped when voltages are balanced, then energy efficiency is improved, but voltage balancing cannot be performed during storage or when charging/discharging is not occurring
Solution Approach 1:
The patent implements a feedback control mechanism where the control unit continuously monitors the voltage states of all cell modules and automatically activates or deactivates the voltage balancing operation based on detected voltage differences. When voltage imbalance is detected, balancing is activated; when voltages are balanced, balancing is deactivated. This feedback loop enables the system to adapt to different operational states including charging, discharging, and storage conditions, providing both energy efficiency and operational flexibility
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 approach reduces wiring congestion and cost, minimizes noise, and allows for stable voltage balancing during charging, discharging, or storage, while determining balanced conditions based on voltage differences rather than current flow, effectively addressing the limitations of previous technologies.
Implementation Method 1
an isolation transformer having a primary winding and a secondary winding
Implementation Method 2
a rectifying circuit connected to the secondary winding of the isolation transformer
Data Source
AI summary
An electricity storage system includes a plurality of storage modules connected in series, each storage module including a single storage cell or a plurality of storage cells connected in series, an isolation transformer and a rectifying circuit that are associated with each of the storage modules, the isolation transformer having a primary winding and a secondary winding, and a voltage balancing circuit that generates an alternating current by switching a direct-current power source, the primary windings of the isolation transformers being all connected in parallel and connected to an output end of the voltage balancing circuit by a common wiring, the secondary windings of the isolation transformers being connected to the corresponding storage modules via the respective rectifying circuits, the alternating current being supplied to the primary winding of each of the isolation transformers.