UPS Inverter Assist Current for Load Variation and Switch Heat

Solution Overview

Problem

Existing uninterruptible power supply devices suffer from low efficiency due to power converter losses and require large semiconductor switches to handle load variations, leading to device upsizing and increased costs.

Innovation Solution

An uninterruptible power supply device with a semiconductor switch and inverter that supplies an assist current from the inverter when load current exceeds a threshold, maintaining current flow below the switch's capacity and preventing overheating, thus using a smaller switch.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a large-capacity semiconductor switch is used to handle load variations, then the device can tolerate load current increases, but the device size and cost increase

Engineering Contradiction:

Improveload variation toleranceVSAvoiddevice size

Core Design Contradiction:

Adaptability or versatilityVSWeight of stationary object

Solution Approach 1:

The patent combines the semiconductor switch with an inverter unit to form a hybrid power supply system. The inverter compensates for the switch's current limitations, allowing the use of a smaller, more cost-effective switch while maintaining the ability to handle load variations through coordinated operation of both components.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The system dynamically changes operational parameters by switching between different power feed modes (bypass mode and inverter mode) based on load conditions. This allows the system to adapt to load variations without requiring the semiconductor switch to continuously handle peak currents, thereby reducing the required switch capacity.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If a large-capacity semiconductor switch is used to handle load variations, then the device can tolerate load current increases, but the manufacturing cost increases

Engineering Contradiction:

Improveload variation toleranceVSAvoidmanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent combines the semiconductor switch with an inverter unit to form a hybrid power supply system. The inverter compensates for the switch's current limitations, allowing the use of a smaller, more cost-effective switch while maintaining the ability to handle load variations through coordinated operation of both components.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The system dynamically changes operational parameters by switching between different power feed modes (bypass mode and inverter mode) based on load conditions. This allows the system to adapt to load variations without requiring the semiconductor switch to continuously handle peak currents, thereby reducing the required switch capacity and associated costs.

Inventive Principle:

Principle #35Parameter changes

3Loss of energy

If the semiconductor switch is used to supply rated current, then the device achieves high efficiency, but the switch overheats when load current exceeds threshold

Engineering Contradiction:

Improvepower lossVSAvoidswitch temperature

Core Design Contradiction:

Loss of energyVSTemperature

Solution Approach 1:

The system dynamically adjusts the power feed mode based on real-time load conditions. When load current exceeds the switch's safe operating threshold, the system transitions from bypass mode to inverter mode, distributing the current load appropriately and preventing thermal overload while maintaining overall system efficiency.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The inverter acts as an intermediary component that takes over part of the current supply responsibility when the semiconductor switch approaches its thermal limits. This mediator role allows the switch to operate within safe temperature ranges while the inverter handles the additional load, preventing overheating without sacrificing efficiency.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 device maintains stable operation during load variations without overheating, enabling downsizing and cost reduction by avoiding the need for large-capacity semiconductor switches.

Implementation Method 1

an inverter that converts DC power supplied from a DC power supply into AC power and supplies the AC power to the load

Methodology Applied

Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

a semiconductor switch connected between a first AC power supply and a load, and turned on when the first AC power supply is normal

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS20250357781A1Uninterruptible power supply device

Publication Date: 2025.11.20 TMEIC CORP

AI summary

This uninterruptible power supply device includes: a semiconductor switch that is connected between a bypass AC power supply and a load, is turned on when the bypass AC power supply is normal, and is turned off when the bypass AC power supply has a power failure; and an inverter that converts DC power supplied from an AC power supply or a battery into AC power and supplies the AC power to the load when the bypass AC power supply has a power failure, and supplies an assist current to the load if a load current is larger than a threshold current when the bypass AC power supply is normal, the assist current being a difference between the load current and the threshold current. Therefore, even if the load current is increased by load variation, the current flowing through the semiconductor switch can be maintained at the threshold current or lower.