PFC and DC-DC Multiplexing Converter for Single-Battery UPS EMC
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Solution Overview
Problem
Existing single-battery uninterruptible power supplies with dual BOOST circuit topology face issues of poor electromagnetic compatibility due to high frequency jumps in battery electrode potentials, leading to increased heating and inefficiency, and require larger inductors, resulting in bulkier and costlier designs.
Innovation Solution
A power factor correction (PFC) and DC-DC multiplexing converter with a multiplexing bridge arm and battery hookup bridge arm, where one electrode of the battery alternately or constantly connects to the neutral point, allowing the inductor to store energy and charge capacitors in both power and battery modes, reducing frequency jumps and improving integration and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If dual BOOST circuit topology is used for multiplexing AC-DC PFC and DC-DC discharge circuits, then the number of power devices is reduced and size is reduced, but electromagnetic compatibility deteriorates due to high frequency jumps in battery electrode potentials
Solution Approach 1:
The patent divides the single battery into separate positive and negative battery circuits, with independent control for each polarity. This segmentation allows the positive and negative sides to operate alternately rather than simultaneously, reducing the frequency of potential jumps at each battery electrode and improving electromagnetic compatibility while maintaining the compact dual BOOST topology.
2Device complexity
If dual BOOST circuit topology is used with alternating operation of positive and negative sides, then integration is improved, but heating increases due to continuous current flow in inductors
Solution Approach 1:
The patent implements periodic action by having the positive and negative sides operate alternately in discrete phases. During each phase, only one side's inductor carries continuous current while the other side's inductor is idle or in a different state. This periodic alternation reduces the average heating in each inductor compared to simultaneous operation, allowing for more compact inductor designs.
3Reliability
If separate design of AC-DC PFC circuit and DC-DC discharge circuit is used, then reliability is improved, but size and cost increase
Solution Approach 1:
The patent applies universality by designing the dual BOOST circuit to serve multiple functions: the same power devices and inductors are used for both AC-DC power factor correction and DC-DC battery discharge operations. The circuit can operate in different modes (utility power mode and battery mode) using the same hardware, reducing size and cost while maintaining reliability through proper mode switching and control.
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
The solution enhances electromagnetic compatibility, reduces heating, and minimizes the size and cost of single-battery uninterruptible power supplies by utilizing a single inductor and improving conversion efficiency in both power and battery modes.
Implementation Method 1
a first inductor, where a first terminal of the first inductor is selectively connected to utility power or a battery... the PFC and DC-DC multiplexing converter controls one electrode of a positive electrode and a negative electrode of the battery to be alternately connected to the neutral point and one of the positive and negative direct current buses
Implementation Method 2
power factor control is performed on alternating current utility power through pulse-width modulation of a positive side switching transistor Q11 and a negative side switching transistor Q12
Implementation Method 3
a first capacitor and a second capacitor respectively connected between the positive and negative direct current buses and the neutral point
Data Source
Figure 1~2
Figure 3
Figure 4a~4b
AI summary
The present invention provides a power factor correction (PFC) and DC-DC multiplexing converter and an uninterruptible power supply including the same. The multiplexing converter includes a multiplexing bridge arm and a battery hookup bridge arm. During power supply of a battery, the converter controls one electrode of a positive electrode and a negative electrode of the battery to be alternately connected to a neutral point and one of positive and negative direct current buses that has the same polarity as the electrode, to enable a level of the electrode of the battery to synchronously and alternately rise or drop with the alternate supply of power to the positive and negative direct current buses; or controls one electrode of a positive electrode and a negative electrode of the battery to be constantly connected to the neutral point. A current converter of the present invention has less battery charge-discharge potential jumps, higher level of integration, lower costs, and better electromagnetic compatibility characteristics, and is more applicable to a single-battery uninterruptible power supply system.