Variable Frequency Drive Double-Circuit Air Cooling
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Solution Overview
Problem
Existing high-voltage electrical equipment cooling systems face issues with increased dimensions, maintainability, and efficiency due to complex designs and inefficient air flow schemes, leading to potential failures and reduced performance.
Innovation Solution
A double-circuit forced air cooling system is implemented in a sealed compartment of a variable frequency drive (VFD) cabinet, featuring internal and external air circuits with circulation and blast fans, and thermoelectric devices to enhance cooling efficiency and maintainability, while maintaining compact dimensions and tightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a forced air cooling system is implemented in a sealed compartment, then cooling efficiency is improved, but device complexity increases
Solution Approach 1:
The cooling system is divided into two separate air circuits: a sealed internal circuit (first air circuit) and an external ventilated circuit (second air circuit). Each circuit operates independently with its own fans and heat exchangers, allowing the complex cooling function to be segmented into manageable parts that can be designed and maintained separately.
Solution Approach 2:
Heat exchangers serve as intermediary devices that transfer thermal energy between the internal and external air circuits without allowing direct mixing of the two air streams. This mediator enables efficient heat removal from the sealed compartment while maintaining the separation and independence of the two circuits.
2Temperature
If multiple fans are installed for cooling, then cooling performance is improved, but cabinet dimensions increase
Solution Approach 1:
Multiple fans are strategically positioned and coordinated to work together as a unified cooling system. The circulation fan and blast fan are integrated into the same sealed compartment, with their air flows combining to achieve effective cooling without requiring additional external space or increasing cabinet dimensions.
Solution Approach 2:
The cooling system utilizes three-dimensional air flow patterns within the sealed compartment, with fans positioned at different locations to create vertical and horizontal air circulation. This spatial arrangement of fans in different dimensions allows efficient cooling coverage without increasing the external footprint of the cabinet.
3Object-affected harmful factors
If a sealed compartment is used with double-circuit cooling, then protection from external temperatures and moisture is improved, but maintainability deteriorates
Solution Approach 1:
The sealed compartment is divided into functional zones with separate access points for different components. The first air circuit (internal) and second air circuit (external) are separated, allowing maintenance personnel to access and service specific components like fans and heat exchangers without compromising the overall sealed structure or requiring complete disassembly.
Solution Approach 2:
Key components such as the circulation fan and heat exchangers are positioned and designed to be extractable or replaceable from the sealed compartment. This allows individual components to be removed for maintenance or replacement while the sealed enclosure remains intact, balancing protection requirements with maintainability needs.
4Temperature
If heat exchangers are positioned inside the sealed compartment, then cooling efficiency is improved, but device complexity increases
Solution Approach 1:
The heat exchangers are positioned within the sealed compartment in a nested arrangement where the second air circuit (external) is strategically placed adjacent to the first air circuit (internal). This nested configuration allows the heat exchangers to efficiently transfer heat between the two circuits while maintaining a compact structure that minimizes overall device 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 improves maintainability, reduces dimensions, and enhances the ergonomic and cooling efficiency of VFDs by creating a compact, efficient cooling system that protects electronic components from external temperatures and moisture, adhering to standards like NEMA4 or IP58.
Implementation Method 1
a circulation fan, which forms a first air circuit, moving the cooling air around and through of each of the local modules
Implementation Method 2
The first air circuit and second air circuit are designed in thermal communication via a number of air heat exchangers installed within the ventilated compartment
Implementation Method 3
a second pair of air heat exchangers is equipped with blast fan. The second air circuit contains straight air channels arranged within the ventilated compartment
Data Source
AI summary
A forced double-circuit air cooling system designed for using in a sealed cabinet structure. A first air circuit is formed by an air loop moved around each of local modules (3; 4) of a sealed compartment [2] with using a circulation fan (26) which is installed within a sealed air channel [28]. The first air circuit is formed within an internal air channel (18) of the sealed compartment [2]. Wherein the internal air channel is connected to a number of air heat exchangers [22]. A first pair [22.1] of said number of air heat exchangers is equipped with the circulation fan [26]. Wherein a second air circuit [25] contains straight air channels [23] arranged within the ventilated compartment [24] adjacent to the sealed compartment [2]. Each of said straight air channels [23] comprising a second pair [22.2] of air heat exchangers with a blast fan [27] between them.