Three-Phase UPS Arc Extinguishing Control Circuit
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Solution Overview
Problem
Existing uninterruptible power supply devices for three phases operate unstably when configured by merely providing three single-phase devices, leading to unbalanced operation.
Innovation Solution
A continuous commercial power supply-type uninterruptible power supply device with first to third output terminals, switches without self arc extinguishing capability, power converters driven by DC power, an abnormality detector, and current detectors, controlled by a circuit to manage switches and power converters, ensuring balanced operation by extinguishing arcs and maintaining a sum of direct currents at zero when AC voltages become abnormal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If three single-phase uninterruptible power supply devices are provided to configure a three-phase device, then the device can be manufactured with simple structure, but the operation becomes unbalanced and unstable
Solution Approach 1:
The patent merges three single-phase uninterruptible power supply devices into a unified three-phase system with common control circuitry and synchronized switching operations. The control circuit coordinates the switching of all three phases simultaneously, ensuring balanced operation while maintaining the manufacturing simplicity of using standard single-phase components.
2Device complexity
If switches without self arc extinguishing capability are used, then the device structure can be simplified, but arcs in the switches cannot be extinguished quickly when AC voltage becomes abnormal
Solution Approach 1:
The patent introduces a current controller as an intermediary device that manages the switching operations of switches without self arc extinguishing capability. The controller coordinates the switching timing and monitors current flow to ensure safe operation, enabling the use of simpler switch structures while maintaining reliable arc extinguishing through controlled switching sequences.
3Device complexity
If the sum of direct currents from power converters is not controlled to zero, then the control system can be simpler, but the three-phase operation becomes unbalanced
Solution Approach 1:
The patent implements a feedback control mechanism where the control circuit continuously monitors the sum of direct currents from the power converters and adjusts the switching commands to maintain the sum at zero. This feedback loop ensures balanced three-phase operation while providing clear control signals to the power converters, achieving stability without excessive system complexity.
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 achieves stable operation of three-phase uninterruptible power supply devices by controlling switches and power converters to balance currents and extinguish arcs, ensuring continuous power supply.
Implementation Method 1
direct current (DC) power supplied from a DC power supply is converted into AC power by the power converter and supplied to the load
Implementation Method 2
arcs in the first to third switches are extinguished
Data Source
AI summary
When three phase AC voltages (Vi1 to Vi3) from a commercial AC power supply (51) become abnormal, a control circuit (6) of an uninterruptible power supply device provides an OFF command signal to first to third switches (1a to 1c), and causes first to third power converters (2a to 2c) to output first to third direct currents, respectively, and quickly extinguish arcs in the first to third switches (1a to 1c). On this occasion, polarities of the first to third direct currents are the same as polarities of currents (Is1 to Is3) flowing into the first to third switches (1a to 1c), respectively, and the sum of values of the first to third direct currents is 0.