SiC Inverter Thermal Integration for Compact Electric Drives

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional electric drive systems face challenges in achieving a lightweight, high-efficiency, and high-temperature operation due to the limitations of silicon inverters, which require large space and operate at lower ambient temperatures with lower efficiency.

Innovation Solution

A lightweight, high-switching-frequency Silicon Carbide (SiC) inverter is used, integrated with a robust thermal management system that includes a radiator, fan, and coolant pump within a single housing, eliminating external coolant tubes and hoses, and achieving a built-in thermal management system for efficient heat removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional silicon inverters are used, then the system can operate at lower ambient temperatures, but the system requires large space and has lower efficiency

Engineering Contradiction:
ImproveefficiencyVSAvoidspace
Core Design Contradiction:
ProductivityVSArea of stationary object

Solution Approach 1:

The patent transitions from conventional silicon inverters to SiC-based inverters, changing the material parameter to enable higher switching frequencies and improved efficiency while reducing the physical space required for the inverter unit

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If external coolant tubes and hoses are used for thermal management, then the system can be simpler to manufacture, but the system architecture becomes more complex and reliability decreases

Engineering Contradiction:
ImprovearchitectureVSAvoidreliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent integrates the thermal management system directly into the inverter housing, merging the cooling function with the structural housing to eliminate external coolant tubes and hoses, thereby simplifying architecture and improving reliability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The inverter housing itself provides the cooling function through integrated coolant channels, making the structure self-sufficient for thermal management without requiring separate external cooling components

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If silicon inverters are used, then the system can be manufactured with conventional materials, but the system achieves lower efficiency and requires larger space

Engineering Contradiction:
ImprovemanufacturingVSAvoidefficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent employs SiC (silicon carbide) semiconductor materials in the inverter, utilizing advanced composite material properties to achieve superior efficiency and power density compared to conventional silicon-based inverters

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

The solution enables a highly efficient (over 93%) electric drive system capable of handling 250 kW peak loads and 85 kW constant loads, suitable for heavy-duty vehicles, with a compact design that simplifies architecture and enhances reliability.

Implementation Method 1

a first heat exchanger coupled to a surface of the electric motor, the first heat exchanger including coolant channels formed in the surface of the electric motor

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

Coolant flows axially through the stator along the power electronics, then radially to channels for cooling the rotor

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3912842B1Lightweight high-efficiency, high temperature electric drive system
Publication Date: 2024.01.03 DEERE & CO
  • EP3912842B1 patent drawingFigure 1A
  • EP3912842B1 patent drawingFigure 1B
  • EP3912842B1 patent drawingFigure 2A

AI summary

A lightweight high-efficiency, high temperature electric drive system includes an electric motor including an output shaft, power electronics electrically coupled to the electric motor, wherein the power electronic include an inverter, a gearbox coupled to the output shaft, a first heat exchanger coupled to a surface of the electric motor, the first heat exchanger including coolant, and a second heat exchanger coupled to a surface of the power electronics, the second heat exchanger including the coolant.