UPS Dynamic Mode Switching for Power Density
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Solution Overview
Problem
Existing UPS systems face inefficiencies in operating modes and power factor correction across varying input voltage conditions, particularly in IT applications where loads are tolerant of wide voltage and frequency variations but require backup power and voltage magnitude limitation.
Innovation Solution
A UPS system with a controller that dynamically switches between online and standby modes based on input voltage magnitude, using a bypass circuit and inverter to provide power conditioning and charging, while operating as a line current conditioner in standby mode, and transitioning to online mode when input voltage exceeds a threshold, thereby optimizing power density and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UPS operates as an online UPS for all input voltage conditions, then the output voltage is always regulated and protected, but the power density and efficiency are reduced due to continuous operation of the rectifier and inverter
Solution Approach 1:
The UPS system dynamically switches between online and standby modes based on input voltage conditions. The controller monitors the input voltage and transitions the UPS to standby mode when the voltage is within acceptable ranges, and to online mode when voltage exceeds thresholds. This dynamic operation optimizes power density by avoiding continuous rectifier and inverter operation while maintaining output protection when needed.
2Reliability
If the UPS operates as an online UPS for all input voltage conditions, then the output voltage is always regulated and protected, but the efficiency is reduced due to continuous operation of the rectifier and inverter
Solution Approach 1:
The system dynamically adjusts its operating mode based on real-time voltage conditions. During normal voltage conditions, the UPS operates in standby mode with minimal energy loss. When voltage sags or swells occur, the controller automatically transitions to online mode to provide voltage regulation, then returns to standby mode when conditions normalize. This dynamic switching minimizes energy losses associated with continuous rectifier and inverter operation.
3Object-generated harmful factors
If the UPS provides continuous power conditioning, then the input current harmonic distortion is reduced and power factor is improved, but the power density and efficiency are reduced
Solution Approach 1:
Power conditioning functions are activated periodically based on voltage conditions rather than continuously. The controller monitors input voltage and enables power factor correction and harmonic filtering only when voltage exceeds acceptable thresholds or during transient conditions. During normal operating conditions, these functions are deactivated, allowing the system to operate in efficient standby mode while still providing protection when needed.
Data Source
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AI summary
A power supply system (100) includes an AC input (Va,Vb,Vc) configured to be coupled to an AC source, an AC output (Va,Vb,Vc') configured to be coupled to a load, a UPS (101) having an input coupled to the AC input (Va,Vb,Vc) and an output coupled to the AC output (Va,Vb,Vc') and a bypass circuit (160) coupled between the AC input (Va,Vb,Vc) and the AC output (Va,Vb,Vc') and configured to open and close a bypass path therebetween. The system further includes a controller (180) configured to control the UPS and the bypass circuit (160) such that the UPS (101) operates as an online UPS for a first input voltage magnitude condition at the AC input (Va,Vb,Vc) and as a standby UPS for a second input voltage magnitude condition at the AC input (Va,Vb,Vc). A multi-mode converter may be coupled to a DC link (112a,112b) of the UPS and configured to be selectively coupled to a battery (170) and the AC input (Va,Vb,Vc) to respectively support battery conversion and current control at the AC input (Va,Vb,Vc) in respective first and second modes of operation of the UPS (101).