Integrated DC-DC Converter UPS Topology
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Solution Overview
Problem
Conventional uninterruptible power supplies (UPS) have high component count, size, and cost, and lack independent control over DC bus voltage levels, leading to inefficiencies and increased losses due to hard switching and the need for additional filters.
Innovation Solution
A UPS topology that includes a PFC converter, a DC-DC converter operating at a fixed 50% duty cycle, and an inverter, which reduces component count by utilizing PFC converter components in the DC-DC converter, allowing independent regulation of DC bus voltages and reducing ripple current and switching losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional UPS topology is used with separate PFC converter and DC-DC converter, then the system provides uninterrupted power supply, but the component count and device size increase
Solution Approach 1:
The patent combines the PFC converter and DC-DC converter into a single integrated converter unit. The same converter operates in PFC mode during normal AC operation and switches to DC-DC converter mode during battery operation, eliminating the need for separate converter components and reducing overall device complexity while maintaining uninterrupted power supply functionality
Solution Approach 2:
The integrated converter is designed to perform multiple functions: it operates as a PFC converter when AC power is available and as a DC-DC converter when battery power is used. This multi-functionality allows a single component to replace what would traditionally require separate dedicated converters, reducing component count while ensuring continuous power supply
2Power
If conventional UPS topology with hard switching is used, then power conversion is achieved, but switching losses and ripple current increase
Solution Approach 1:
The patent implements soft switching techniques where the converter transitions between operating modes smoothly. The controller manages the switching transitions to minimize abrupt changes, reducing switching losses and ripple current while maintaining effective power conversion from both AC and DC sources
3Ease of operation
If conventional UPS topology is used without independent DC bus control, then simpler control is achieved, but DC bus voltage levels cannot be independently regulated
Solution Approach 1:
The controller dynamically adjusts operating parameters to enable independent DC bus voltage regulation. By changing control parameters based on operating mode (PFC or DC-DC), the system achieves independent voltage control on both positive and negative DC buses while maintaining relatively simple control architecture through mode-based parameter adjustment
4Volume of moving object
If higher frequency operation is implemented, then transformer size can be reduced, but switching losses increase
Solution Approach 1:
The system dynamically optimizes switching frequency based on operating conditions. By implementing soft switching and managing transitions smoothly, the system can operate at higher frequencies to reduce transformer size while minimizing the increase in switching losses through controlled dynamic operation
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 topology minimizes component count and size, reduces costs, and enables independent DC bus voltage control, while achieving lower switching losses and reduced ripple current, allowing for higher frequency operation and smaller transformer size.
Implementation Method 1
operate, in an online mode of operation, the PFC converter to provide regulated DC power, derived from the input AC power
Implementation Method 2
operate, in a backup mode of operation, the DC-DC converter to convert the backup DC power to unregulated power
Implementation Method 3
a transformer coupled to the first plurality of switches
Data Source
AI summary
According to one aspect, embodiments of the invention provide a UPS comprising a line input, an interface configured to be coupled to a DC power source, an output, a PFC converter, a positive DC bus coupled to the PFC converter and configured to provide a positive DC output, a negative DC bus coupled to the PFC converter and configured to provide a negative DC output, a DC-DC converter coupled to the interface, and a controller configured to operate, in an online mode of operation, the PFC converter to provide regulated DC power, derived from input AC power, to the positive DC bus and the negative DC bus, and operate, in a backup mode of operation, the DC-DC converter to convert backup DC power to unregulated power, and the PFC converter to provide regulated DC power, derived from the unregulated power, to the positive DC bus and the negative DC bus.