Circular Motor Drive Power Plane for Cooler VFD Electronics
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Solution Overview
Problem
Variable frequency drive electronics are sensitive to high temperatures, leading to improper operation or premature failure when combined with motor assemblies, as they generate excessive heat that exceeds safe operating conditions.
Innovation Solution
A motor assembly design incorporating a mid-plate and end-plate with internal and external radial cooling fins, along with an insulation layer, to efficiently conduct and convect heat away from the electronics, reducing thermal contact and allowing for effective heat dissipation within the motor envelope.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If variable frequency drive electronics are installed inside the motor assembly, then power density is increased and variable speed operation is achieved, but the electronics are exposed to high temperatures that cause improper operation or premature failure
Solution Approach 1:
The motor assembly is divided into distinct thermal zones using a mid-plate with internal cooling fins and an end-plate with external cooling fins. The electronics are segregated into a dedicated compartment isolated from the high-temperature motor operating environment, allowing the electronics to operate at lower temperatures while the motor can operate at higher temperatures for improved power density.
Solution Approach 2:
The mid-plate and end-plate with cooling fins act as thermal intermediaries between the motor and electronics. These plates conduct heat away from the electronics compartment through the fin structures, creating a thermal barrier that protects the temperature-sensitive electronics while allowing the motor to operate at higher temperatures.
2Power
If the electronics are operated at maximum rating in the high temperature environment, then power output is maximized, but the electronics fail prematurely
Solution Approach 1:
Different parts of the motor assembly are assigned different thermal characteristics. The electronics compartment is designed with heat dissipation features (cooling fins) to maintain a locally cooler environment suitable for electronics operation, while the motor portion can operate at higher temperatures for maximum power output. This local differentiation allows both power maximization and extended service life.
3Temperature
If cooling fins are added to the mid-plate and end-plate, then heat dissipation capability is improved, but device complexity increases
Solution Approach 1:
The mid-plate and end-plate are designed to serve multiple functions simultaneously: they provide structural support for the motor assembly, act as mounting surfaces for the electronics, and function as heat dissipation devices through the integrated cooling fins. This multi-functionality reduces the need for separate cooling components, thereby managing complexity while improving heat dissipation.
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 design increases power density and reduces the sensitivity of variable frequency drive electronics to high temperatures, enabling their safe operation within the motor assembly by maintaining temperatures below their maximum rating, thus preventing premature failure.
Implementation Method 1
internal radial cooling fins extending from the inner circumference of the central portion and diverging outwardly towards the peripheral portion to transfer heat from the central portion to the peripheral portion allowing for internal conduction heat capability
Implementation Method 2
external radial cooling fins diverging outwardly away from the plate to transfer the heat to surrounding air allowing for external convection heat capability
Implementation Method 3
an insulation layer configured to reduce thermal contact between the at least one plate and a power plane having electrical components
Data Source
AI summary
A motor assembly for driving a pump or rotary device features a power plane with a circular geometry to be mounted inside a space envelope having a similar circular geometry formed on an end-plate between an inner hub portion and a peripheral portion that extends circumferentially around the space envelope of the end-plate. The power plane is a multi-layer circuit board or assembly having: a power layer with higher temperature power modules for providing power to a motor, a control layer with lower temperature control electronics modules for controlling the power provided to the motor, and a thermal barrier and printed circuit board layer between the power layer and the control layer that provides electrical connection paths between the power modules of the power plane and the control electronics modules of the control layer, and also provides insulation between the power layer and the control layer.