Transformer-Based Voltage Equalization for Series Energy Storage
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Solution Overview
Problem
Energy-storage elements such as batteries and capacitors often have inconsistent terminal voltages due to capacity, resistance, and environmental factors, leading to overvoltage, undervoltage, and reduced service life when connected in series, necessitating voltage equalization to ensure proper usage and longevity.
Innovation Solution
A device comprising a transformer with equalizing and transforming windings, and bi-directional DC/AC converter circuits, which converts and equalizes the terminal voltages of energy-storage elements by using a transformer to isolate and transform voltages between equalizing buses, allowing for proportional voltage equalization across multiple energy-storage elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple energy-storage elements are connected in series to increase voltage, then the overall voltage output is improved, but voltage inconsistency and overvoltage issues occur among individual units
Solution Approach 1:
The patent introduces a transformer as an intermediary device with multiple windings corresponding to different energy-storage elements. The transformer mediates voltage distribution by providing isolated transformation paths for each unit, enabling proportional voltage equalization while maintaining series connection benefits. This resolves the contradiction by adding a mediating component that balances voltage without requiring direct parallel connections.
Solution Approach 2:
The patent changes the voltage transformation ratio parameter of the transformer windings to achieve proportional voltage equalization. By adjusting the turns ratio of each winding, the system can compensate for capacity and resistance differences among energy-storage elements, maintaining voltage consistency while preserving the series connection structure for high voltage output.
2Reliability
If traditional voltage equalization methods are used, then voltage balance is improved, but system complexity and cost increase due to multiple DC/DC converters
Solution Approach 1:
The patent merges the voltage equalization function with the existing transformer isolation and transformation functions. Instead of adding separate DC/DC converter modules for each energy-storage element, the invention utilizes the transformer's multiple windings to simultaneously achieve isolation, transformation, and equalization in a single integrated component, significantly reducing system complexity.
Solution Approach 2:
The transformer in the patent serves multiple functions: electrical isolation between primary and secondary sides, voltage transformation to different levels, and voltage equalization across multiple energy-storage elements. This multi-functionality eliminates the need for dedicated equalization converters, reducing both device quantity and system complexity while maintaining effective voltage balance.
3Adaptability or versatility
If energy-storage elements with different capacities are used to meet varying energy demands, then system adaptability is improved, but voltage inconsistency worsens due to capacity variance
Solution Approach 1:
The patent applies local quality by providing customized transformation ratios for each winding of the transformer according to the specific capacity characteristics of each energy-storage element. Each winding is designed with appropriate turns ratio to compensate for the individual unit's capacity, resistance, and leakage current characteristics, enabling voltage equalization tailored to local differences while maintaining overall system adaptability.
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 equalizes voltages across energy-storage elements, preventing overvoltage and undervoltage issues, optimizing the performance and lifespan of battery and capacitor groups by ensuring all units operate at a consistent ratio, allowing for efficient energy distribution and utilization.
Implementation Method 1
using a transformer to isolate and transform voltages between equalizing buses
Implementation Method 2
bi-directional DC/AC converter circuits, which converts and equalizes the terminal voltages
Data Source
AI summary
A device (3) and a method for equalizing the voltage of an energy-storage element (4) are provided herein. The device (3) comprises at least one transformer (36) and at least one bi-directional DC/AC converter circuit (35). Each transformer (36) comprises at least one equalizing winding (30) and at least one transforming winding (26,27). The DC terminals of each DC/AC converter circuit (35) is adapted to connect to a positive terminal (41) and a negative terminal (42) of the energy-storage element (4), and the AC terminals thereoft is connected with the transforming winding (26,27) of the transformer (36).