SiC-FWD 2-in-1 Power Module for Railway Car Thermal Management
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Solution Overview
Problem
The existing 2-in-1 power semiconductor modules face challenges in reducing size for railway car applications due to heat management issues, particularly in regenerative modes, where FWD chips exceed allowable temperatures, necessitating larger coolers and increased costs.
Innovation Solution
Incorporating silicon carbide (SiC) diodes in the 2-in-1 module to reduce ON voltage and recovery losses, allowing for a configuration that balances IGBT and FWD chip sizes, enabling the use of existing 1-in-1 modules without size increase, and utilizing SiC-FWDs to equalize temperature rises with IGBTs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the size of FWD chips is increased to handle regenerative mode current, then the FWD can dissipate heat effectively, but the module size increases and costs increase
Solution Approach 1:
The patent changes the material parameter of the FWD from silicon to wide band gap semiconductor, which fundamentally alters the thermal and electrical properties. This material parameter change enables the FWD to handle high current and dissipate heat effectively without requiring increased chip size, thus resolving the contradiction between temperature management and module size reduction
Solution Approach 2:
The patent employs composite material structure by integrating wide band gap semiconductor material into the FWD component. This composite approach combines the advantages of wide band gap materials (high temperature stability, high breakdown voltage) with the existing module architecture, enabling effective heat dissipation without increasing overall module dimensions
2Volume of moving object
If the size of IGBT chips is reduced to allocate space to FWD chips, then more space is available for FWD, but the electric current capacity in power running mode becomes insufficient
Solution Approach 1:
The patent applies parameter change to the FWD material composition, using wide band gap semiconductor which enables higher breakdown voltage and current handling capability per unit area. This allows the FWD to occupy more area without compromising overall module power capacity, as the wide band gap material provides superior electrical performance at smaller dimensions
3Power
If six 1-in-1 modules are used to ensure sufficient electric current capacity, then the power running mode current capacity is adequate, but the apparatus size cannot be reduced
Solution Approach 1:
The patent merges two separate modules (first 1-in-1 module with IGBTs and second 1-in-1 module with FWDs) into a single integrated 2-in-1 module. The wide band gap FWDs enable compact design while maintaining full power capacity, allowing the inverter to be configured with only three 2-in-1 modules instead of six 1-in-1 modules, thus reducing apparatus size by half
Solution Approach 2:
The patent uses composite material technology with wide band gap semiconductors to create a unified 2-in-1 module structure that combines both IGBT and FWD functions. This composite approach enables the integrated module to handle both power running mode and regenerative mode currents effectively, achieving space reduction while maintaining full operational capability
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 approach allows for a compact 2-in-1 power semiconductor module that can be used in railway cars, reducing module size, cooler size, and costs while maintaining reliable operation within temperature limits.
Implementation Method 1
the first and second diode elements are formed of wideband gap semiconductor
Implementation Method 2
a cooler (heat dissipation device) configured to cool the IGBT chips and the FWD chips
Data Source
AI summary
A power semiconductor module applied to a power converting apparatus for a railway car includes an element pair formed by connecting an IGBT and an SiC-FWD in anti-parallel to each other and an element pair formed by connecting an Si-IGBT and an SiC-FWD in anti-parallel to each other. The element pair and the element pair are housed in one module and configured as a 2-in-1 module in a manner that the first element pair operates as a positive side arm of the power converting apparatus and the second element pair operates as a negative side arm of the power converting apparatus. The element pairs are formed such that a ratio of an occupied area of SiC-FWD chips to an occupied area of IGBT chips in the element pairs is equal to or higher than 15% and lower than 45%.