Power electronics cooling arrangement

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Solution Overview

Problem

Existing refrigerant compressors face challenges in efficiently cooling power electronics, especially in high saturated suction temperature (SST) applications where the low pressure difference can lead to uneven cooling.

Innovation Solution

A refrigerant compressor with a cooling line that can be switched between two modes: one mode dumps refrigerant between the first and second stages, while the second mode dumps refrigerant upstream of the first stage, allowing for adaptive cooling based on operating conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If refrigerant is dumped between the first and second stages for cooling power electronics, then cooling is provided to the power electronics, but in high SST applications the pressure difference is low leading to uneven cooling

Engineering Contradiction:
Improvecooling efficiencyVSAvoidcooling uniformity
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The system dynamically switches between two cooling modes based on operating conditions. A controller monitors parameters such as suction pressure and SST, and automatically selects the appropriate cooling mode (inter-stage or upstream) to optimize cooling performance for the current operating conditions, thereby resolving the contradiction between providing cooling and ensuring uniform cooling distribution.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the operational parameters of the cooling system by switching the refrigerant dump location between two positions: between stages for normal conditions and upstream of the first stage for high SST conditions. This parameter change allows the system to adapt to different operating conditions and maintain effective cooling uniformity across varying pressure differentials.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If a single cooling mode is used for all operating conditions, then the system structure is simple, but the system cannot adapt to high SST applications with low pressure difference

Engineering Contradiction:
Improveadaptability to different operating conditionsVSAvoidcooling line configuration
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The cooling line is designed with multi-functionality to serve different cooling needs. By incorporating switching means (such as valves or plugs) that can direct refrigerant flow to different locations, the same cooling line structure can adapt to various operating conditions including normal SST and high SST applications, thereby achieving versatility without proportionally increasing complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The cooling system incorporates dynamic switching capability through controller-operated valves or movable plugs that can reconfigure the refrigerant flow path based on real-time operating conditions. This dynamic adaptation allows the system to handle diverse applications (normal and high SST) while maintaining a relatively compact and integrated design, balancing adaptability with structural simplicity.

Inventive Principle:
Principle #15Dynamics

3Temperature

If refrigerant is returned to the suction side in high SST applications, then cooling efficiency is improved by utilizing lower temperature and pressure, but requires a switchable cooling line configuration

Engineering Contradiction:
Improvecooling effectivenessVSAvoidcooling line switching mechanism
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The system employs dynamic switching mechanisms (valves or plugs controlled by a controller) that can reconfigure the cooling line to return refrigerant to the suction side when high SST conditions are detected. This dynamic capability allows the system to exploit the lower temperature and pressure at the suction side for improved cooling effectiveness only when needed, rather than requiring a permanently complex configuration.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The controller automatically monitors operating conditions (such as suction pressure and SST) and autonomously switches the cooling mode without requiring external intervention. The system serves itself by detecting when high SST conditions exist and automatically directing refrigerant to the suction side, thereby achieving improved cooling effectiveness while minimizing the operational complexity for the user.

Inventive Principle:
Principle #25Self-service

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 solution enables improved cooling efficiency in high SST applications by allowing refrigerant to be returned to the suction side, which has a lower temperature and pressure, thereby preventing overheating and optimizing system performance.

Implementation Method 1

the cooling line is configured to cool power electronics

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

Refrigerant loops are known to include a condenser, an expansion device, and an evaporator

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP4007871B1Power electronics cooling arrangement
Publication Date: 2025.02.19 DANFOSS AS
  • EP4007871B1 patent drawingFigure 1
  • EP4007871B1 patent drawingFigure 2
  • EP4007871B1 patent drawingFigure 3

AI summary

A refrigerant compressor according to an exemplary aspect of the present disclosure includes, among other things, a first stage and a second stage downstream of the first stage, and a cooling line configured to cool power electronics. The cooling line is configured to be switched between a first mode and a second mode. The first mode is configured to dump refrigerant between the first stage and the second stage, and the second mode is configured to dump refrigerant upstream of the first stage.