Reconfigurable UPS Inverter Circuit for AC/DC Source Switching
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Solution Overview
Problem
Existing uninterruptible power supplies (UPS) face challenges in reducing costs and increasing power density while maintaining independent voltage functionality without altering the frequency of the power grid, particularly when transitioning between AC and DC power sources.
Innovation Solution
An uninterruptible power supply circuit that integrates a power factor correction circuit and an inverter circuit, allowing for a first configuration to supply power from a second AC power grid and a second configuration to supply power from a DC voltage source, sharing components like an inductor and switch branches between these circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate circuits are used for AC/AC conversion and DC/AC conversion, then functional independence is maintained, but device complexity and cost increase
Solution Approach 1:
The patent implements a unified power conversion circuit that can operate in multiple modes: AC/AC conversion during normal operation and DC/AC conversion during grid faults. The circuit shares common components including the inverter stage, output filter, and control unit, while using configuration switches to reconfigure the input stage for different operating modes, thereby reducing device complexity while maintaining functional independence
2Device complexity
If components are pooled between AC/AC and DC/AC circuits, then cost and device volume are reduced, but adaptability to different power sources decreases
Solution Approach 1:
The patent employs dynamic reconfiguration of the circuit topology through control switches that can change the connection configuration of the input stage. During AC/AC operation, the power factor correction circuit is connected to the AC input; during DC/AC operation, the DC voltage source is connected to the same input stage. This dynamic switching capability allows the same hardware to adapt to different power sources without compromising performance
3Reliability
If AC/AC conversion is used during normal operation, then power quality is improved, but cost and power density are reduced
Solution Approach 1:
The patent merges the AC/AC and DC/AC conversion circuits into a single unified power conversion system. The power factor correction circuit, inverter stage, and output filter are shared between both conversion modes. By eliminating redundant components and using a common DC link, the design achieves both power quality improvement and cost reduction while maintaining the ability to handle grid faults
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 integration improves component utilization and reduces costs and bulk without altering the frequency of the power grid, ensuring uninterrupted power supply during AC grid faults by utilizing a DC voltage source.
Implementation Method 1
a first stage correcting a power factor taken from the electrical system and converting the AC voltage of the power grid into a DC voltage
Implementation Method 2
an inverter stage converting the DC voltage into an AC voltage that is delivered to the electrical system
Implementation Method 3
said power factor correction circuit comprising an inductor
Data Source
AI summary
An uninterruptible power supply circuit includes an inverter circuit configured to be connected to a first AC power grid, the power supply circuit moreover being configured to adopt a first configuration for supplying power to the first AC power grid from a second AC power grid, wherein first configuration a power factor correction circuit is configured to be connected to the second AC power grid so as to deliver a DC voltage to the inverter circuit, the power factor correction circuit comprising an inductor, and a first switch branch pertaining to the power factor correction circuit and the inverter circuit; and a second configuration for supplying power to the first AC power grid from a DC voltage source, wherein second configuration a DC-DC converter circuit is configured to be connected to the DC voltage source so as to deliver a DC voltage to the inverter circuit, the inductor moreover pertaining to the DC-DC converter circuit.