Voltage Converters for Parallel Battery Voltage Equalization
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Solution Overview
Problem
Connecting power storage units with large voltage differences in parallel leads to excessive current flow and potential deterioration due to high voltage spikes when switching elements are turned on or off, as existing systems lack effective voltage equalization methods.
Innovation Solution
A power supply system with voltage converters and current measuring instruments that determine a reference power storage unit and remaining units, adjusting voltage conversion ratios to minimize current differences and equalize voltages or SOCs, thereby preventing unit deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plurality of power storage units having large voltage differences are connected in parallel, then voltage equalization can be achieved, but large current flows and high voltage spikes are generated causing deterioration of power storage units
Solution Approach 1:
A voltage converter is introduced as an intermediary device between power storage units with large voltage differences to enable safe parallel connection. The voltage converter converts voltages at arbitrary ratios, allowing units with different voltages to be connected without generating harmful large currents or voltage spikes, thus achieving voltage equalization while preventing deterioration
Solution Approach 2:
The voltage converter dynamically adjusts the voltage conversion ratio to control the charging and discharging currents between power storage units. By changing the voltage parameters adaptively, the system equalizes voltages while maintaining current levels within safe operating limits
2Reliability
If voltage converters are used to connect power storage units in parallel, then voltage equalization is achieved, but the system complexity increases
Solution Approach 1:
The voltage converter is designed with multi-functionality, serving both as a voltage matching device and as a controlled current transfer mechanism. This single device handles multiple tasks (voltage conversion, current control, isolation), reducing the need for additional separate components and simplifying the overall system
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 system effectively equalizes voltages or SOCs among power storage units while preventing excessive current flows, thus avoiding deterioration and ensuring efficient operation.
Implementation Method 1
voltage converters configured to convert voltages of a plurality of power storage units connected to input sides at arbitrary voltage conversion ratios, and output the converted voltages to output sides
Implementation Method 2
current measuring instruments connected to input sides of the plurality of voltage converters, respectively, and configured to measure currents flowing from the plurality of power storage units to the input sides
Data Source
AI summary
In a power supply system and a method for controlling the same, at least one battery from among a plurality of batteries is designated as a charging-side battery, and the remaining batteries are designated as discharging-side batteries. Next, the difference in current between the current flowing from the discharging-side batteries and the current flowing into the charging-side battery is determined on the basis of currents measured by a plurality of current measuring instruments. Next, the transformation rate of a voltage transformer connected to the discharging-side batteries is determined on the basis of the determined difference in current.