UPS Circuit Bypassing Input Converter for Rapid Battery Charging
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Solution Overview
Problem
Conventional UPS architectures face challenges in rapidly recharging batteries using modern technologies like LiFePO4 without significantly increasing the power rating and cost of converter circuits, limiting the recovery time and autonomy of the system.
Innovation Solution
The introduction of a bidirectional converter that bypasses the input converter to supply charging current directly to the battery, allowing for increased charging rates without increasing the power rating of the input converter, and the use of parallel paths to supplement power during overload conditions, reducing the overall power handling requirements of the converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the charging current is increased to rapidly recharge the battery using modern battery technologies, then the recovery time of autonomy is reduced, but the power rating of the input converter must be significantly increased
Solution Approach 1:
The patent divides the charging function into two separate converters: the input converter handles power conversion from the mains supply, while the further converter (charging converter) handles battery charging. This segmentation allows the input converter to maintain its original power rating while the further converter provides the high charging current needed for rapid battery recovery, thus resolving the contradiction between fast charging and input converter power rating.
Solution Approach 2:
The further converter acts as an intermediary component between the input converter and the battery. It receives power from the input converter and provides the high charging current to the battery, enabling rapid recharging without requiring the input converter to be oversized. This intermediary solution allows the system to achieve fast battery recovery while keeping the input converter at its original power rating.
2Productivity
If the power rating of the input converter is increased to provide both conditioned supply to load and high charging current to battery, then the charging rate is improved, but the cost of the circuitry is disproportionately increased
Solution Approach 1:
By segmenting the power conversion functions into separate converters, the patent avoids the need to oversize the input converter. The further converter is specifically designed for high-current battery charging, while the input converter maintains its standard power rating. This segmentation enables high charging rates without the disproportionate cost increase that would result from upgrading the input converter's power rating.
3Device complexity
If a single converter is used to provide both conditioned power supply to load and charging current to battery, then the device complexity is reduced, but the power rating and cost of the converter must be significantly increased
Solution Approach 1:
The patent accepts increased device complexity by introducing a separate further converter dedicated to battery charging. This segmentation allows the input converter to maintain its original power rating, avoiding the need for a significantly oversized single converter. The trade-off of added complexity is justified by the avoidance of disproportionate power rating increases and associated costs.
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 enables rapid battery recharging and recovery of autonomy within 20-30 minutes after a discharge event without a disproportionate increase in component costs, leveraging the potential of advanced battery technologies while minimizing the power ratings of the converter circuits.
Implementation Method 1
a further converter operable to provide a charging current supply to said battery from a charging supply input
Implementation Method 2
converted by said input converter and output converter in series to provide an output power supply via said supply output to a load
Implementation Method 3
converted by said input converter and output converter in series to provide an output power supply
Implementation Method 4
An essential element of a UPS is a battery which provides the power after switch over has occurred
Data Source
AI summary
An uninterruptible power supply operates between a main supply input, a battery and a load, and comprises an input converter and an output converter. In a first mode of operation, AC mains power received at the supply input is converted by said input converter and output converter in series to provide an AC power supply to the load. In a second mode of operation, stored energy is released from the battery via the output converter to maintain the AC power supply to the load. A further converter can be used during the first mode of operation to charge the battery from a charging supply input. The charging current bypasses the input converter, allowing charging rate to be increased, without increasing a power rating of the input converter. The further converter may be bidirectional and be used also in the second mode.