Modular UPS with Segmented PFC Converters
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Solution Overview
Problem
Conventional three-phase AC input UPS systems suffer from poor input power factor, high input current distortion, and inefficiency, with high power systems requiring split battery inputs, making them costly, complex, and inflexible, and lacking scalability in output power conversion.
Innovation Solution
The UPS system employs multiple single-phase AC-to-DC converters and an interconnect circuit to manage three-phase AC input power, allowing flexible operation modes and redundancy, with a controller managing the distribution of power between AC input and DC power sources to optimize power conversion and output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single PFC converter is used for all three input phases, then the system structure is simplified, but the input power factor deteriorates and input current distortion increases
Solution Approach 1:
The patent divides the single PFC converter into three separate single-phase PFC converters, each handling one phase independently. This segmentation allows each converter to operate optimally for its phase, improving input power factor and reducing current distortion while maintaining manageable system complexity through modular design
2Power
If split battery input is used for high power UPS systems, then the charging capability is improved, but the system cost and complexity increase
Solution Approach 1:
The patent merges the battery charging function into a single unified DC bus that serves all three phases. Instead of requiring separate battery inputs for each phase, the rectified DC voltage from any phase can charge the common battery and power the DC bus, simplifying the system while maintaining adequate charging capability
3Power
If conventional high power UPS systems are designed, then the output power capacity is increased, but the flexibility in scaling and connecting input power sources is reduced
Solution Approach 1:
The patent segments the UPS system into three independent single-phase modules, each with its own PFC converter. This modular architecture allows flexible scaling where modules can be added or removed based on power requirements, and enables adaptable input configurations where different combinations of single-phase or three-phase inputs can be connected without redesigning the entire 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
This configuration enhances efficiency, reduces complexity and cost, and provides scalable, flexible power management with improved input power factor and reduced distortion, enabling unity power factor operation and seamless backup power supply.
Implementation Method 1
a first single-phase AC-to-DC converter, a second single-phase AC-to-DC converter configured to receive a second phase of the three-phase AC input power and convert the second phase to a DC voltage
Data Source
AI summary
An uninterruptible power supply system (UPS) includes an interconnect circuit configured to receive three-phase AC input power from an AC power source and a plurality of UPS subsystems each coupled to the interconnect circuit. A first UPS subsystem includes first and second single-phase AC-to-DC converters. At least one second UPS subsystem includes third and fourth single-phase AC-to-DC converters. In a first mode of operation, the interconnect circuit is configured to conduct at least one phase of the AC input power to the first UPS subsystem and at least one phase of the AC input power to the second UPS subsystem, and, in a second mode of operation, to disconnect the AC input power from the first UPS subsystem and to conduct at least one phase of the AC input power to the second UPS subsystem.