UPS Parallel Converter Efficiency Control

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Solution Overview

Problem

Uninterruptable power supply (UPS) systems with multiple parallel converters face inefficiencies at varying load levels, leading to increased energy consumption and operational costs due to unnecessary converter activation and standby losses.

Innovation Solution

A method and system for controlling UPS systems by determining the optimal number of active converters based on system load levels and efficiency curves, allowing for efficient operation with reduced losses by activating only the necessary converters and maintaining others in standby states with minimal power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple converters are activated to support the load, then the load capacity and reliability are improved, but the energy consumption and losses increase

Engineering Contradiction:
ImprovereliabilityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The system dynamically adjusts the number of active converters based on real-time load conditions. The control device continuously monitors the load level and activates or deactivates converters to match the actual power requirements, ensuring that converters are not left running at low utilization rates which would waste energy while maintaining reliability when load demands it.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the operational parameters of the UPS system by transitioning converters between different states (active, standby, deactivated) based on load level. This parameter change allows the system to optimize the balance between reliability and energy consumption by adjusting the operational state of converters rather than maintaining a fixed configuration.

Inventive Principle:
Principle #35Parameter changes

2Speed

If converters are kept in standby state to provide redundancy, then the response time to load changes is improved, but the base load losses increase

Engineering Contradiction:
Improveresponse timeVSAvoidbase load losses
Core Design Contradiction:
SpeedVSLoss of energy

Solution Approach 1:

The system dynamically manages converter states based on actual load conditions. Instead of maintaining fixed standby converters, the control device adjusts which converters remain in standby mode and which can be deactivated, optimizing the trade-off between having ready reserves for rapid response and minimizing the energy consumed by idle converters.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention applies partial action by maintaining only the necessary number of standby converters rather than keeping all converters in standby. The control device determines the optimal number of standby converters needed based on load level, avoiding the excessive energy consumption that would result from keeping all converters in standby state while still providing adequate response capability.

Inventive Principle:
Principle #16Partial or excessive action

3Power

If the number of active converters is increased, then the system can handle higher load levels, but the system efficiency decreases due to increased losses

Engineering Contradiction:
Improveload capacityVSAvoidsystem efficiency
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The system dynamically optimizes the number of active converters based on real-time load monitoring. The control device calculates the optimal configuration by considering both the power delivery requirements and the efficiency characteristics of converters at different load levels, activating only the necessary number of converters to meet the current load demand.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control device uses feedback from load level monitoring to continuously optimize converter configuration. By monitoring the actual load and comparing it with the efficiency characteristics of the converters, the system adjusts the number of active converters to maintain optimal efficiency while meeting power delivery requirements.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3088989B1UPS operation with high converter efficiency
Publication Date: 2018.01.17 ABB (SCHWEIZ) AG
  • EP3088989B1 patent drawingFigure 1
  • EP3088989B1 patent drawingFigure 2~3
  • EP3088989B1 patent drawingFigure 4

AI summary

The present invention provides a method for controlling an uninterrupted power supply system (100) comprising multiple converters (102) and a control device (122), whereby the multiple converters (102) are connected in parallel between a power supply side (104) and a load side (106) of the uninterrupted power supply system (100), each converter (102) is provided to be individually activated by the control device (122) to provide power from the power supply side (104) to the load side (106), comprising the steps of determining a system load level at the load side (106) of the uninterruptable power supply system (100), determining a number of required active converters (102) based on the system load level and a system efficiency depending on the number of active converters (102), and activating the number of required converters (102) based on the above determination. The present invention further provides a respective uninterruptable power supply system (100) comprising multiple converters (102) and a control device (122), whereby the multiple converters (102) are connected in parallel between a power supply side (104) and a load side (106) of the uninterrupted power supply system (100), and the control device (122) performs the above method.