Power Electronics Module Thermal Management via Segmented PCB Layout

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Solution Overview

Problem

Conventional power electronics modules (PEMs) in high power charger applications for electric and hybrid vehicles face challenges in space utilization, thermal management, and electromagnetic interference (EMI) due to the integral arrangement of high voltage, high power PCBs and low voltage, low power PCBs, which leads to inefficient cooling and increased costs.

Innovation Solution

The PEM design separates the hot AC input filter portion from the main power section and mounts it vertically on a sidewall, with the main power section adjacent to a lower chassis heatsink for effective cooling, and positions the low voltage, low power PCB above for EMI isolation. Magnetic components are enclosed in thermally conductive plastic with molded pin fins to enhance heat transfer, and the lower chassis heatsink is integrated with coolant conduits and fin structures for improved thermal management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If high voltage, high power PCBs and low voltage, low power PCBs are arranged in an integral or side-by-side configuration, then space utilization is improved, but thermal management becomes difficult and EMI problems increase

Engineering Contradiction:

Improvespace utilizationVSAvoidthermal management

Core Design Contradiction:

Volume of moving objectVSTemperature

Solution Approach 1:

The patent divides the PCB arrangement into separate functional sections: high voltage/high power PCBs are positioned adjacent to the lower chassis heatsink for dedicated thermal management, while low voltage/low power PCBs are placed on opposite sides away from heat-generating components. This segmentation allows each section to be optimized independently for both space utilization and thermal management.

Inventive Principle:

Principle #1Segmentation

2Temperature

If high voltage, high power PCBs are placed close to cooling sources, then thermal management is improved, but EMI affects low voltage, low power PCBs

Engineering Contradiction:

Improvecooling efficiencyVSAvoidEMI interference

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent extracts low voltage/low power PCBs from proximity to high voltage/high power components and places them on opposite sides of the housing. This physical separation removes sensitive low voltage circuits from the harmful electromagnetic field generated by high voltage components, while high voltage PCBs remain optimally positioned for thermal management near the lower chassis heatsink.

Inventive Principle:

Principle #2Taking out (Extraction)

3Object-affected harmful factors

If magnetic components are enclosed in thermally conductive plastic enclosures, then EMI shielding is improved, but heat transfer becomes challenging

Engineering Contradiction:

ImproveEMI shieldingVSAvoidheat transfer

Core Design Contradiction:

Object-affected harmful factorsVSTemperature

Solution Approach 1:

The patent employs thermally conductive plastic enclosures that combine electromagnetic shielding properties with thermal conduction capabilities. These composite material enclosures allow heat to pass through to the heatsink while simultaneously providing EMI shielding for the magnetic components, resolving the contradiction between thermal management and electromagnetic interference protection.

Inventive Principle:

Principle #40Composite materials

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 arrangement minimizes space usage, optimizes cooling for high voltage, high power components, isolates low voltage, low power PCBs from EMI, and enhances thermal management, resulting in a more efficient and cost-effective power electronics module with improved power density and reduced thermal resistance.

Implementation Method 1

magnetic components are enclosed within one or more injection molded thermally conductive plastic enclosures with molded pin fins on the bottom thereof that are configured to enhance heat transfer to or through the lower chassis heatsink

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

conduits may be incorporated into the volume of the lower chassis heatsink and the housing itself, with fin or pin structures disposed in portions of the coolant flow to enhance heat transfer from the lower chassis heatsink to the coolant flow

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 3

fin or pin structures disposed in portions of the coolant flow to enhance heat transfer from the lower chassis heatsink to the coolant flow via increased heat transfer surface area

Methodology Applied

Scientific EffectHeat transfer surface area enhancement: Heat Exchanger

Data Source

PatentUS11683918B2Power electronics module with improved space utilization and thermal management characteristics

Publication Date: 2023.06.20 RIVIAN HOLDINGS LLC

AI summary

A power electronics module for an industrial or vehicle battery charger system or the like is provided. The power electronics module utilizes a chassis housing including a heatsink surface and a plurality of sidewalls. A main power section printed circuit board is disposed adjacent to the heatsink surface of the chassis housing a. A low voltage, low power printed circuit board is disposed adjacent to the main power section printed circuit board opposite the heatsink surface of the chassis housing. An alternating current input filter portion printed circuit board including electromagnetics is disposed along one of the plurality of sidewalls of the chassis housing and separated from the low voltage, low power printed circuit board within the chassis housing.