Isolated Low-Voltage UPS Storage With HF Conversion for Data Centers
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Solution Overview
Problem
Data centers face challenges in managing high power and medium voltage requirements, especially during power interruptions, due to increasing electricity demands and the need for efficient energy storage solutions that minimize electrical losses and power usage effectiveness (PUE).
Innovation Solution
A bi-directional high-frequency DC-DC converter with isolation, utilizing low-voltage energy storage devices, H-bridge circuits, and high-frequency transformers, along with a phase-shifted zero voltage switching (ZVS) controller, to efficiently charge or discharge energy storage devices and provide a high DC voltage output, enabling effective power management in data centers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If low-voltage energy storage devices are used to meet high power requirements, then energy storage capacity is improved, but voltage level is insufficient for medium voltage applications
Solution Approach 1:
The system divides the voltage transformation into multiple stages using series-connected H-bridge circuits. Each H-bridge processes a portion of the total voltage requirement, enabling the system to handle medium voltage levels while maintaining compatibility with low-voltage energy storage devices. This segmentation allows progressive voltage building without requiring high-voltage energy storage components.
Solution Approach 2:
The patent introduces a multi-dimensional voltage transformation approach by combining series connections of H-bridges with high-frequency transformation. This creates additional voltage multiplication dimensions, transforming low-voltage energy storage into medium-voltage output through coordinated switching and transformation stages.
2Reliability
If conventional low-frequency transformers are used for magnetic isolation, then isolation reliability is improved, but device size and volume increase
Solution Approach 1:
The system changes the operating frequency parameter from conventional low-frequency (50/60 Hz) to high-frequency operation. This parameter change enables the use of smaller magnetic components while maintaining isolation reliability, as high-frequency transformers require less magnetic material for the same power transmission capability.
Solution Approach 2:
The patent replaces conventional low-frequency magnetic isolation mechanisms with high-frequency electromagnetic transformation. This substitution enables more compact isolation architecture while maintaining the essential isolation function through faster switching and smaller magnetic footprints.
3Volume of stationary object
If high-frequency switching is used to reduce transformer size, then device volume is reduced, but switching losses increase
Solution Approach 1:
The system extracts and addresses the switching loss problem separately by implementing zero-voltage switching (ZVS) techniques. This allows the high-frequency operation to proceed with minimal energy loss, as the switching transitions occur when voltage is zero, eliminating capacitive switching losses.
Solution Approach 2:
The H-bridge circuits serve multiple functions simultaneously: voltage transformation, magnetic isolation, and loss mitigation through coordinated switching. This multi-functionality enables the system to achieve high-frequency operation with reduced losses by optimizing each component for multiple roles.
4Loss of energy
If medium voltage operation is implemented to reduce electrical losses, then power usage effectiveness is improved, but voltage compatibility with standard energy storage devices is lost
Solution Approach 1:
The system introduces H-bridge circuits and high-frequency transformers as intermediary components between low-voltage energy storage devices and medium-voltage loads. These intermediaries enable voltage level translation, allowing standard low-voltage energy storage to serve medium-voltage applications while maintaining voltage compatibility at both ends.
Solution Approach 2:
The voltage transformation is segmented into discrete stages through series-connected H-bridges, each handling a portion of the voltage conversion. This segmentation maintains adaptability by allowing modular configuration while achieving the overall medium voltage output needed to reduce electrical losses.
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 switching losses, minimizes the size and volume of magnetic isolation, and provides a reliable, efficient power supply with reduced electromagnetic interference, effectively addressing the high power and medium voltage needs of data centers during power interruptions.
Implementation Method 1
a high frequency transformer, to efficiently charge or discharge energy storage devices and provide a high DC voltage output
Implementation Method 2
a phase-shifted zero voltage switching (ZVS) controller, to efficiently charge or discharge energy storage devices
Data Source
AI summary
Systems and methods of this disclosure use low voltage energy storage devices to supply power at a medium voltage from an uninterruptible power supply (UPS) to a data center load. The UPS includes a low voltage energy storage device (ultracapacitor/battery), a high frequency (HF) bidirectional DC-DC converter, and a multi-level (ML) inverter. The HF DC-DC converter uses a plurality of HF planar transformers, multiple H-bridge circuits, and gate drivers for driving IGBT devices to generate a medium DC voltage from the ultracapacitor/battery energy storage. The gate drivers are controlled by a zero voltage switching (ZVS) controller, which introduces a phase shift between the voltage on the primary and secondary sides of the transformers. When the primary side leads the secondary side, the ultracapacitor/battery discharges and causes the UPS to supply power to the data center, and when the secondary side leads the primary side, power flows from the grid back to the UPS, thereby recharging the ultracapacitor/battery.